1.

Atomic Theory 1

Question Answer Mark

Number
1(a)(i) From top to bottom
Proton
Electron
Neutron 3

Question Answer Mark

Number
3(a)(ii) 8 1

Question Answer Mark

Number
3(a)(iii) Be / Beryllium 1

Question Answer Mark

Number
3(b) x Same number of protons / atomic number
x Different number of neutrons / mass number /
nucleon number 2

Question
Answer Notes Marks
number
2 (a) electron(s) 1

(b) electron(s) 1

Accept in either order both

(c) (i) protons (and) electrons 1
answers

(ii) protons 1

neutrons 1

(d) (i) 12 1

(ii) 24 1

(iii) 2.8.2 Accept any other punctuation

marks, such as , / ) — and no 1
punctuation marks

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 Question Ma
Expected Answer Accept Reject
number rks
3 (a) M1 both protons = 6 1

M2 C-13 has 7 and C-14 has 8 (neutrons) 1

(b) same electronic configuration(s) / structure(s) different number of 1
protons
OR
1.Atomic Theory

same number of electrons amount for number / six

Classified Chemistry
OR electrons

have four/same number of electrons in outer /

valence shell

IGNORE same number of electrons in inner shells

IGNORE references to atomic number / same
number of protons / different number of neutrons

(c) (i) M1 the average / mean mass of an atom (of the average/mean of: mean mass of an element 1

1C - Edexcel
element) atomic masses /
mass numbers /
mass of isotopes 1

on a scale where
th
M2 compared to / relative to (1/12 ) the mass carbon-12 has a mass of
(of an atom) of carbon-12 12
/ compared with the
mass of carbon-12
OR which is 12
M1 mass of one mole of atoms
mass of one mole of the
th
M2 compared to (mass of) 1/12 one mole / 1g element
of carbon-12
2

Dr.Ann Mahdy
 Question Mar
Expected Answer Accept Reject
number ks
c (ii) M1 (12 x 98.9) + (13 x 1.1) (12 x 0.989) + (13 x 1
0.011) for first 2 marks
M2 100 1
1.Atomic Theory

M3 12.01 12.011 on its own for 2 1

Classified Chemistry
marks
IGNORE units
12.01 on its own for 3
marks

Question
Answer Notes Marks
number

1C - Edexcel
4 a M1 nucleus 1
M2 protons 1
Accept in either order
M3 neutrons 1
M4 electrons 1
M5 shells 1
M6 protons AND electrons In either order 1
M7 electrons 1
b i 3 1
ii 5 1
3

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
b iii M1 (sodium bromide) ionic bonding / + and – ions Reject covalent bonding / shared 1
electrons
M2 (hydrogen bromide) attraction between Accept dipole-dipole attractions / van 1
molecules der Waals' forces / IMF / vdW
/ intermolecular forces (of attraction) Ignore hydrogen bonds
1.Atomic Theory

Reject ions/ionic
M3 ionic bonding stronger Accept ionic bonds stronger 1

Classified Chemistry
OR M3 dependent on comparison of
IMF / attractions between HBr molecules weaker intermolecular forces and ionic bonding
Accept correct references to energy
needed to overcome bonding /
attractions
Ignore references to reactivity and
mass
c M1 Na Br O 0/3 if division by atomic number(s) 1
13.8 47.9 38.3 /division wrong way round
23 80 16 If only two elements shown correctly,

1C - Edexcel
only M1 can be awarded
M2 0.6 0.6 2.4 Accept 1 : 1: 4 1
M3 NaBrO4 Accept elements in any order 1
Penalise M3 for incorrect symbol, eg
SBrO4 or NaBO4
Dividing by 160 instead of 80 gives
Na2BrO8
Dividing by 32 instead of 16 gives
NaBrO2
Award 2 in these cases
Both these errors give Na2BrO4
Award 1 in this case
Correct final answer scores 3 marks
5

Dr.Ann Mahdy
Total 16
 Question
Answer Notes Marks
number
6 (a) (i) A = proton(s) Award 1 mark for two correct
particles in the wrong order
B = neutron(s) 2
1.Atomic Theory

(ii) atomic number = 5 No mark for two numbers transposed

Classified Chemistry
mass number = 11 2

(b) (i) boron 1

(ii) 2, 3 ACCEPT any other punctuation marks, 1

such as ‘.’ ‘/’ ‘-‘ or no punctuation

Total: 6

1C - Edexcel
6

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
7 (a) i 5 1

ii 11 1
1.Atomic Theory

iii 5 1

Classified Chemistry
iv 6 1

v 5 1

(b) i more 1

ii more 1

iii the same number of 1

1C - Edexcel
(c) cross in box D (2.8.3) 1
Total 9
7

Dr.Ann Mahdy
 Question
Expected Answer Accept Reject Marks
number
8 (a) (i) 12 1

(ii) M1 – 2 roman numeral 1

1.Atomic Theory

M2 – two electrons in outer/valence shell 1

Classified Chemistry
Award M2 if M1 missing but not if incorrect
Ignore references to magnesium and 2.8.2

(iii) X2+ Mg2+ 1

(b) M1 – (79 x 24) + (10 x 25) + (11 x 26) (0.79 x 24) + (0.10 x 25) + (0.11 1
x 26) for 2 marks
M2 – divide by 100 1

M3 – 24.3 24.32 with no working scores 2 1

1C - Edexcel
Mark M2 and M3 csq on M1 if one minor
slip in numbers in M1 (eg 97 instead of 79
or 25 instead of 24)

M3 dep on M2

Correct answer with no working scores 3

IGNORE units

(Total marks for Question 3 = 7 marks)

Dr.Ann Mahdy
8
 Question
Answer Notes Marks
number
9 a 1
1.Atomic Theory

Classified Chemistry
b i A (an electron) 1

ii B (a neutron) 1

iii B (electrons and protons) 1

c isotopes
atomic numbers 3

1C - Edexcel
mass numbers

Total 7 marks

Question
Answer Notes Marks
number
10 a i 4 1

ii B (hydrated) 1

Dr.Ann Mahdy
9
 Question
Answer Notes Marks
number
11 f 85 AND 87 calculated (even if not identified) Accept 37+48 and 37+50 1
(85 × 0.72) + (87 × 0.28) = 85.6 Correct final answer = 2 marks 1
85.5 or 85.56 = 1 mark
No ECF from incorrect mass numbers
1.Atomic Theory

Ignore units

Classified Chemistry
Question
Answer Notes Marks
number
12 (a) C (halogens) 1

1C - Edexcel
Dr.Ann Mahdy
10
 Question
Answer Notes Marks
number
(b) (i) M1 atoms of the same element accept ‘atoms with the same atomic 1
number’ / ‘atoms with the same number
of protons’
1
M2 with different masses
accept ‘different mass numbers’ /
1.Atomic Theory

‘different numbers of neutrons’

Classified Chemistry
ignore references to electrons unless
incorrect

(ii)
Isotope Number Number Number 3
of of of
protons neutrons electrons
Br 35 44 35

1C - Edexcel
Br 35 46 35

M1 first column correct

M2 second column correct
M3 third column correct
11

Dr.Ann Mahdy
 1.Atomic Theory 12

Question
Answer Notes Marks
number
13 (b) (i) M1 atoms of the same element atoms with same 2
atomic number /
atoms same number
of protons

M2 with different masses different mass

numbers / different
numbers of neutrons

IGNORE references to
electrons unless
incorrect

(ii) H
1
H
2
H
3 one mark for each 3
protons 1 1 1 correct row
neutrons 0 1 2
electrons 1 1 1

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 Question
Answer Notes Marks
number

14 (a) (i) M1 A and B 3

1.Atomic Theory

M2 they have the same numbers of DEP on correct choice of letters

protons Accept same atomic number

Classified Chemistry
Ignore references to electrons

M3 the numbers of protons and electrons are Allow M3 if at least two from A, B and E given
equal for M1
Ignore references to neutrons

Statement about equal/same numbers of

protons and electrons scores M2 and M3

(ii) M1 G and H 3

1C - Edexcel
M2 they have the same numbers of DEP on correct choice of letters
protons
Accept same atomic number
Ignore references to electrons

M3 there are more electrons than protons Allow M3 if at least two from D, F, G, H given
for M1

Ignore references to neutrons

Dr.Ann Mahdy
13
 (iii) M1 A 2

M2 it has the fewest (total number of) DEP on correct choice of letter
protons and neutrons
Accept fewest nucleons
1.Atomic Theory

Accept because its mass number is 10

Classified Chemistry
Allow (A) because mass number is (sum of) the
number of protons and neutrons

Ignore references to electrons

(iv) 2.5 Accept comma and other punctuation marks 1

Accept diagram showing electrons on circles

1C - Edexcel
(b) M1 setting out of calculation eg (24 × 0.786) + (25 × 0.101) + (26 ×
0.113)
M2 evaluation
24.327 / 24.33
M3 answer to 1 dp
24.3
Ignore units
3
Correct final answer with no working scores 3
marks

Dr.Ann Mahdy
14

(Total for Question 4 = 12 marks)

 Question Answer Mark
Number
1(a) Mg 1

Question Answer Mark

Number
1(b) C 1
2.Periodic Table

Question Answer Mark

Classified Chemistry
Number
1(c) O (accept 8) 1

Question Answer Mark

Number
1(d) 2 / alkaline earth 1

Question Answer Mark

Number
1(e) 7 / halogen 1

1C - Edexcel
Question
Expected Answer Accept Reject Marks
number
2 (a) (increasing) atomic number(s) proton number / number mass number / 1
of protons RAM
IGNORE references to electrons / electronic
configurations

(b) (i) sodium / potassium Na / K 1

(ii) fluorine / chlorine / bromine F / Cl / Br / F2 / Cl2 / Br2 fluoride / 1

chloride /
bromide
15

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
3 (a) An explanation linking the following points: ACCEPT full outer(most) shell
x 8 electrons in outer(most) shell ACCEPT argument based on energy
x does not easily/readily gain or lose electrons required 2

(b) 8 electrons in middle shell ACCEPT dots, circles, crosses or e to

2.Periodic Table

represent electrons
7 electrons in outer shell 2

Classified Chemistry
Question
Answer Accept Reject Marks
number
4 (a) M1 electronic configuration / 2.1, 2.8.1, 2.8.8.1 electronic structure / 1
arrangement of electrons

1C - Edexcel
M2 same number of electrons in outer shell / one 1
electron in outer shell

OR

the number of electrons in the outer shell determines

the chemical properties

(b) melting point / melting temperature 1

16

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
5 (a) (i) A (Ag) 1

(ii) D (Zr) 1

(b) (i) 3 1
2.Periodic Table

(ii) (The atom has) three electrons in its outer / ‘energy level’ for ‘shell’ 1

Classified Chemistry
valence shell ignore references to inner shells
ignore ‘it has a valency of 3’

(iii) 3 1

(iv) (The atom has) electrons in three shells / three ‘energy levels’ for ‘shells’ 1
shells are occupied (with electrons) accept ‘it has three shells’

(v) aluminium / Al 1

1C - Edexcel
(c) accept any symbol for electrons, eg dots, 1
the letter ‘e’
17

Dr.Ann Mahdy
 2.Periodic Table 18

Question
Answer Notes Marks
number
6 (a) (i) E 6

(ii) B

(iii) F

(iv) C

(v) F

(vi) E

(b) (i) M1 (bonding/shared) electrons 2

M2 nuclei ACCEPT protons /

nucleus(es)
OR

M1 nuclei ACCEPT
nucleus(es)
M2 bonding/shared electrons

(ii) A2D / DA2 ACCEPT H2O 1

REJECT if charges
shown

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 Question
Answer Notes Marks
number
7 a atomic number Accept proton number 1
Accept number of protons

b (relative) atomic mass Reject mass number 1

2.Periodic Table

Classified Chemistry
c i electrons 1

ii electrons 1

iii protons AND neutrons Names can be in either order 1

iv protons AND electrons Names can be in either order 1

v neutrons 1

1C - Edexcel
Question
Answer Notes Marks
number

8 atomic number of the atom 3 5

number of shells shown 2

mass number of the atom 7

number of protons in an isotope 3

of this element

group where element is found in 1

the Periodic Table
19

Dr.Ann Mahdy
(Total for Question 1 = 5 marks)
3.BONDING 20

Question Answer Mark

Number
1(a)(i) Shared pair of electrons 1

Question Answer Mark

Number
1(a)(ii) H × H (accept two × or two ·) 1

Question Answer Mark

Number
1(b) Test – lighted / lit splint
Result – (squeaky) pop / explosion 2

Question Answer Mark

Number
1(c) (manufacture of) ammonia / margarine / HCl 1

Question Answer Mark

Number
1(d) Hydrogen + oxygen → water 1

Question Answer Mark

Number
2(d) x Electrons being transferred between oxygen and
sodium (can be wrong way round)
x Idea of sodium losing electron(s) and oxygen
gaining electron(s)
x Correct number of electrons involved (sodium lose
1, oxygen gain 2)
(sharing = 0 marks) 3

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 Question
Answer Notes Marks
number
3 a i M1 H—O—H with both bonds represented by 2 Accept 2 dots, 2 crosses or 1 of each 1
shared electrons Atoms do not have to be labelled
with H or O
If wrongly labelled, only M1 can be
3.BONDING

awarded
M2 8 electrons in outer shell of O Ignore inner shell of O 1
AND Reject if H has 2 shells
2 electrons in outer shell of both H M2 dependent on M1

Classified Chemistry
ii M1 (strong electrostatic) attraction between Must refer to pair or two electrons 1
bonding/shared pair of electrons
M2 and nuclei (of hydrogen and oxygen) Accept word nucleus instead of nuclei 1
if clear reference to 2 atoms
0/2 if any mention of ions / electron
transfer
M2 dependent on mention of both
attraction and electrons in M1

1C - Edexcel
Question
Answer Notes Marks
number
3 b i M1 idea of electron transfer / loss and gain of 1
electrons
M2 direction of transfer, eg sodium to oxygen / 1
sodium loses and oxygen gains
M3 correct number of electrons involved, eg (each) Ignore charges on ions 1
sodium loses 1 and oxygen gains 2
Ignore covalent
0/3 if any mention of electron
sharing
All marks may be scored on
diagrams or by reference to
21

electronic configurations

Dr.Ann Mahdy
Max 2 if molecules mentioned
 Question
Answer Notes Marks
number
3 c M attractions between water molecules are Allow (named) intermolecular forces 1
1 weak(er) / easily overcome / need little energy in place of attractions
3.BONDING

to break
M attractions between (sodium and oxide) ions are Do not award M2 if any mention of 1
2 strong(er) / ionic bonds are strong /need a lot of intermolecular forces / metallic
energy to break bonding

Classified Chemistry
Any implication of breaking covalent
bonds = 0/2

1C - Edexcel
22

Dr.Ann Mahdy
 Question
Expected Answer Accept Reject Marks
number

4 (c) (i) sodium OR potassium Na / K

AND
fluorine OR chlorine OR bromine OR hydrogen F / Cl / Br / H / F2 / Cl2 / fluoride / 1
3.BONDING

Br2 / H2 chloride /
Answers can be in either order bromide /
hydride
IGNORE incorrect symbols/formulae if names are

Classified Chemistry
correct
(ii) Marks do not have to be CQ on (c)(i), and all marks
can be scored here for correct diagrams of the ions in a
hydrogen halide Incorrect 1
0 electrons
electron
M1 Na or K with 8 electrons transfer for M1
and M2
H with 2 electrons 1
M2 F, Cl or Br with 8 electrons

1C - Edexcel
IGNORE diagrams showing initial electron 1
configurations

M3 (1)+ AND (1)– charges correct

IGNORE inner shells even if incorrect

Allow any combination of dots and crosses

If shown covalently bonded, then max. 1 for correct

charges if given

If the position of 2 electrons shown between the two

23

Dr.Ann Mahdy
species makes it hard to be sure that the bonding is
definitely ionic (and not covalent), do not award M1 or
M2
 Question
Answer Notes Marks
number
5 (a) (i) P3 ACCEPT P3 1

(ii) An explanation linking the following points: REJECT any mention of electron
3.BONDING

x ions are not free to move in solid (IGNORE ref to electrons) movement 2
x (however) ions are free to move when molten

Classified Chemistry
(d) (i) 1 mark for 3 bonding pairs
1 mark for non-bonding pair 2

(ii) An explanation linking any two of the following points:

x small molecules
x weak (attractive) forces between molecules ACCEPT “weak bonds”, but not
x (therefore) little energy required to overcome forces / “weak covalent bonds”
separate molecules max 2

1C - Edexcel
24

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

6 a 4 electrons shared between 2 (carbon) Ignore inner electrons 1

atoms even if wrong Ignore
number of hydrogen
3.BONDING

atoms

Classified Chemistry
4 electron pairs between 2C and 4H atoms 1
Accept all permutations of
dots and crosses
Ignore intersecting circles
Accept H atoms at all
angles
At least one C or one H
atom must be labelled –
max 1 if not
Max 1 if more than 2 C
atoms

1C - Edexcel
Max 1 if wrong number of
electrons in outer shell of
any atom
25

Dr.Ann Mahdy
 Question Mark
Answer Accept Reject
number s
7 (b) 1
3.BONDING

D
(c) 1

Classified Chemistry
A
(d) M1 (consists of) positive AND negative/oppositely 4
charged ions/Mg2+ AND O2— (ions)
IGNORE references to loss and gain of electrons

M2 (strong) attraction between (positive AND (strong) ionic bonding/(strong)

negative/ ionic bonds
oppositely charged) ions/Mg2+ AND O2— (ions)

M3 many ions (present in lattice)/giant

structure/giant lattice

1C - Edexcel
M4 large amount of energy required (to separate the break the ionic bonding/bonds
ions/overcome the attraction between the ions)

If mention of covalent bonds/metallic

bonds/intermolecular forces only M4 can be awarded
26

Dr.Ann Mahdy
 Question
Answer Accept Reject Marks
number
8 (c) (i) M1 - Na loses electron(s) 1
3.BONDING

M2 – Cl gains electron(s) 1

M3 – Na becomes 2.8 AND chlorine becomes 2.8.8 1

Classified Chemistry
If incorrect number of electrons transferred, max 2

IGNORE references to full shells

max 1 for mention of covalent bonding

All 3 marks can be scored from correct dot and

cross diagrams showing electron transfer

1C - Edexcel
(ii) M1 – Na = 23 AND Cl = 35.5 1

M2 – 58.5 1

M2 dep on M1

IGNORE units

Correct answer with no working scores 2

27

Dr.Ann Mahdy
 Question
Answer Accept Reject Marks
number
9 (a) 3
any combination of
dots and crosses
3.BONDING

M1 – for both electron diagrams correct

Classified Chemistry
IGNORE inner electrons of N even if incorrect

M2 – for both charges correct

M3 – for correct ratio of ions

(d) ions cannot move ionic compounds do 1

OR not normally conduct
ionic compounds only conduct when molten/in when solid

1C - Edexcel
solution

IGNORE references to electrons

Question
Answer Notes Marks
number
10 b i 2 (1) (1) 2 Accept multiples and fractions 1

ii all five bonds shown as dot and cross Accept all dots and all crosses 1
rest of diagram correct Accept any combination of dots and crosses 1
M2 DEP on M1
28

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

11 b i covalent Accept sharing electrons 1

3.BONDING

Reject sharing 1 electron

Reject references to ions
Ignore intermolecular forces

Classified Chemistry
Ignore simple
Reject giant

ii intermolecular forces (of Accept intermolecular bonds 1

attraction) / forces (of
attraction) between molecules
weak / need little (thermal/heat) energy Accept easily overcome 1
to
overcome
M2 DEP on M1 at least partially correct
If only answer is weak bonds, then 0/2

1C - Edexcel
If any reference to breaking covalent /ionic /
metallic bonds, then 0/2

iii Mo2O6 1
29

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

12 b i M1 electron transfer AND correct direction If any reference to sharing electrons, 0/3 3
If any reference to covalent bonds, MAX 2
3.BONDING

Penalise atoms in place of electrons each time

M2 magnesium (atoms) lose 2 electrons

M3 (each) chlorine (atom) gains an electron Accept two chlorine (atoms) gain two electrons

Classified Chemistry
Reject chloride in place of chlorine

M2 and M3 both correct also scores M1

ii M1 for electronic configuration of Mg2+ ion 3

M2 for electronic configuration of Cl– ion

M3 for both charges correct

1C - Edexcel
Accept any combination of dots and crosses
Charges can be shown anywhere so long as
there is no ambiguity
Brackets not essential
Ignore 2 before or after chloride ion
0/3 for any diagram showing shared electrons
Ignore diagrams showing electron transfer –
mark only the ions formed
Penalise missing inner shell(s) once only
If two Cl– ions shown, both must be correct
Do not penalise empty third shell in Mg2+
If only 2.8 etc notations without diagram, only
M3 can be awarded
30

Dr.Ann Mahdy
 3.BONDING 31

Question
Answer Notes Marks
number
13 (a) (i) ACCEPT any 1
combination of dots
and crosses
NB H does not need to be shown if
touching / overlapping circles are shown if overlapping /
touching circles used
both electrons must
be within the
overlapping/touching
area

(ii) M1 weak forces (of attraction) between ACCEPT particles 2

molecules / weak intermolecular ACCEPT bonds for
forces forces for both M1
and M2
ACCEPT correctly
named IMF

M2 (therefore) little (thermal/heat) IGNORE more easily

energy required to overcome these separated / easier to
forces / separate the molecules (into break
the gaseous state)
REJECT atoms for
both M1 and M2

NB any mention of
breaking covalent or
ionic bonds scores 0

Question
Answer Notes Marks
number
14 (c) (i) TiCl4 + 2Mg → Ti + 2MgCl2 ACCEPT multiples and 2
halves
M1 all formulae correct IGNORE state symbols
even if incorrect
M2 balanced 1

(ii) titanium / Ti / magnesium / Mg IGNORE refs to oxidation

reacts with oxygen ACCEPT forms an oxide
OR
titanium / Ti / magnesium / Mg
reacts with nitrogen ACCEPT forms a nitride

(iii) magnesium chloride will dissolve IGNORE to speed up the

more quickly / to help the reaction
magnesium chloride to dissolve / IGNORE refs to increasing
more of the magnesium chloride is surface area 1
in contact with the water

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 Question
Answer Notes Marks
number

15 a covalent Ignore references to polar bonding and electron

1
sharing
3.BONDING

Accept bonds for forces for both M1 and M2

Reject atoms for both M1 and M2

Classified Chemistry
b M1 weak forces (of attraction) between Accept particles for molecules
molecules / weak intermolecular forces Accept correctly named IMF eg van der Waals'

M2 (therefore) little (thermal/heat) energy Ignore more easily separated / easier to break
required to overcome the forces / separate the 2
molecules
if any reference to/implication of breaking
covalent or ionic bonds scores 0/2

M1 and M2 indep

1C - Edexcel
c M1 (strong) attraction between bonding/shared
pair of electrons

M2 (and) nuclei of (both atoms) Do not award M2 if reference to only one nucleus
2
OR

M1 bonding/shared pair of electrons

M2 (strongly) attracted to nuclei (of both atoms)

Do not award M2 if reference to only one nucleus

32

Dr.Ann Mahdy
 d M1 for 2 electrons shared between one H and one
Cl

M2 rest of molecule fully correct

M2 DEP on M1
3.BONDING

Accept any combination of dots and crosses

2
Ignore inner shells of electrons in chlorine

Classified Chemistry
if overlapping touching/circles are used both
electrons must be within the overlapping/touching
area

symbols do not need to be shown if overlapping

touching /circles are used

1C - Edexcel
33

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
16 b i M1 shared pair of electrons 1
M2 other electrons correct (not necessary to be 1
3.BONDING

paired)
M2 dependent on M1
Accept any combinations of dots and

Classified Chemistry
crosses
Circles not needed but if drawn must
overlap or touch – if not, then 0/2
Ignore inner electron shells even if
incomplete or incorrect
Do not penalise incorrect symbols, eg br/BR
If Na used in place of H, max 1
No marks if ions shown
ii M1 shared (two/pair of) electrons Not share an electron 1
M2 attracted to both nuclei M2 dependent on M1 or near miss 1
eg the electrons are attracted to the

1C - Edexcel
nucleus scores 0
the electrons are attracted to both nuclei
scores M2 but not M1
0/2 if references to ions / ionic bond /
intermolecular forces
34

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
b iii M1 (sodium bromide) ionic bonding / + and – ions Reject covalent bonding / shared 1
electrons
3.BONDING

M2 (hydrogen bromide) attraction between Accept dipole-dipole attractions / van 1

molecules der Waals' forces / IMF / vdW
/ intermolecular forces (of attraction) Ignore hydrogen bonds

Classified Chemistry
Reject ions/ionic
M3 ionic bonding stronger Accept ionic bonds stronger 1
OR M3 dependent on comparison of
IMF / attractions between HBr molecules weaker intermolecular forces and ionic bonding
Accept correct references to energy
needed to overcome bonding /
attractions
Ignore references to reactivity and
mass

1C - Edexcel
35

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

17 b i M1 electron transfer AND correct direction If any reference to sharing electrons, 0/3 3
If any reference to covalent bonds, MAX 2
3.BONDING

Penalise atoms in place of electrons each time

M2 magnesium (atoms) lose 2 electrons

M3 (each) chlorine (atom) gains an electron Accept two chlorine (atoms) gain two electrons

Classified Chemistry
Reject chloride in place of chlorine

M2 and M3 both correct also scores M1

ii M1 for electronic configuration of Mg2+ ion 3

M2 for electronic configuration of Cl– ion

M3 for both charges correct

1C - Edexcel
Accept any combination of dots and crosses
Charges can be shown anywhere so long as
there is no ambiguity
Brackets not essential
Ignore 2 before or after chloride ion
0/3 for any diagram showing shared electrons
Ignore diagrams showing electron transfer –
mark only the ions formed
Penalise missing inner shell(s) once only
If two Cl– ions shown, both must be correct
Do not penalise empty third shell in Mg2+
If only 2.8 etc notations without diagram, only
M3 can be awarded
36

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

c M1 for 4 electrons in both C=O bonds 2

3.BONDING

These can be shown in a vertical or horizontal line

M2 all other electrons correct

Classified Chemistry
M2 DEP on M1
Accept any combination of dots and crosses
Ignore inner electrons even if wrong
Ignore circles around atoms
Non-bonding electrons do not need to be paired

1C - Edexcel
37

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
1 a i M1 layers / sheets / planes / rows of (positive) ions Allow atoms/ particles in place of 1
positive ions
Reject molecules / protons /
electrons
M2 slide (over each other) Allow slip / flow / move in place of 1
slide

Classified Chemistry
4.SOLID STRUCTURE

Accept explanation in terms of non-

directional bonding
Do not award M2 if protons /
electrons
Do not award M2 if no mention of
layers or equivalent

ii M1 delocalised electrons / sea of electrons Ignore free electrons 1

M2 move / flow (through structure) / mobile M2 needs mention of electrons 1
(when voltage/potential difference applied) Any mention of ions moving = 0/2

1C - Edexcel
38

Dr.Ann Mahdy
 Question
Expected Answer Accept Reject Marks
number

2 (b) (i) M1 oxygen (atom) oxygen molecule / 1

O2 / oxide ion
/oxygen ion
M2 forms two bonds / smaller atom / has more of them (n the diagram 1
valency of 2 / structure)
IGNORE more (oxygen) in the formula

Classified Chemistry
4.SOLID STRUCTURE

M2 DEP on M1, although allow M2 if oxygen

mentioned but M1 not awarded because of
reference to molecule/ion/O2

(ii) M1 giant (structure / lattice / atomic) giant molecular / 1

IGNORE large / 3D macromolecular

M2 covalent 1

1C - Edexcel
M3 idea that covalent bonds are broken 1
IGNORE bonds are loosened overcome for broken

M4 covalent bonds are strong / lots of energy 1

required to break covalent bonds/ lots of heat many bonds are broken = M3
required to break covalent bonds + M4

IGNORE high temperature needed

Do not penalise silicone

Max2 for mention of ionic or metallic bonding

or
intermolecular forces
39

Dr.Ann Mahdy
Max 3 if discussing diamond / carbon
 Question
Answer Notes Marks
number
3 (a) B 1

(b) A 1

(c) D 1

Classified Chemistry
4.SOLID STRUCTURE

(d) C 1

(e) A 1

Total: 5

1C - Edexcel
40

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

4 a i delocalised electrons / sea of Ignore free electrons 1

electrons
move / flow (through M2 needs mention of electrons,
structure) / mobile (when e.g. "electrons move/flow" scores
voltage/potential difference M2 but not M1
applied) Ignore references to carrying

Classified Chemistry
4.SOLID STRUCTURE

charge/current
No penalty for references to
aluminium atoms or ions / nuclei /
protons, but any mention of these
moving = 0/2

ii layers/sheets/planes/rows 1
AND
(positive) Reject
ions/atoms/particles molecules/protons/electrons/nuclei

1C - Edexcel
slide (over each other) Allow 1
slip/flow/shift/roll/move/OWTTE in
place of slide
Do not award M2 if no mention of
layers or equivalent
Do not award M2 if
protons/electrons/nuclei
41

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

b NITROGEN
(simple) molecular structure Accept (nitrogen/N2/small/discrete) molecules 1

intermolecular forces (of Accept intermolecular bonds 1

attraction) Reference to intermolecular also scores M1
/ forces between molecules

Classified Chemistry
4.SOLID STRUCTURE

weak / easily overcome 1

/need little energy to
overcome
If any reference to breaking covalent bonds or
any other type of bonding, only M1 can be
awarded

SILICA
giant (structure) Accept macromolecular 1
Ignore lattice

1C - Edexcel
covalent (bonds) Covalent can be anywhere in answer 1

bonds strong / hard to break 1

/need a lot of energy to break
If any reference to breaking intermolecular
forces or any other type of bonding, only M4
can be awarded
Any five for 1 mark each
Total 9
Total for paper 120
42

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
5 (a) (i) M1 – (covalent) bonds have to be broken any mention of ions / metallic bonding / molecules 1
/ intermolecular forces scores 0/2

M2 – large amount of energy required Accept large number of bonds to be broken 1

/ bonds are strong Accept forces (of attraction) between atoms in place
of bonds

Classified Chemistry
4.SOLID STRUCTURE

(ii) the (covalent) bonding in silicon dioxide is Accept the covalent bonds (in silicon dioxide) are 1
stronger (than the (ionic) bonding in stronger than the ionic bonds (in sodium chloride)
sodium chloride) Accept more energy is required to break the
(covalent) bonds in silicon dioxide (than is required
to break the (ionic) bonds in sodium chloride)
Accept forces (of attraction) between atoms in place
of bonds

(b) ions flow/move (to the electrodes) Accept ions are mobile/can move 1
reject electrons

1C - Edexcel
(c) weak forces (of attraction) between Accept boiling point is below room temperature 1
molecules
reject any mention of covalent bonds broken
/ weak intermolecular forces (of attraction)
/ little energy is required to separate
molecules
43

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

6 b M1 (neodymium ions in) layers/rows/planes/sheets/OWTTE Accept atoms/cations/particles for ions

Reject molecules

M2 slide/slip (over each other) Allow OWTTE, eg flow/shift/roll/move

Classified Chemistry
4.SOLID STRUCTURE

M2 DEP on mention of EITHER

layers or equivalent
OR mention of ions or equivalent

Do not award M2 if
molecules/protons/electrons/nuclei in
place of ions etc 4

If reference to ionic bonding / covalent

bonding /molecules / intermolecular

1C - Edexcel
forces, no marks

Not just electrons

M3 delocalised electrons OR sea of electrons
Ignore free electrons

Ignore carry charge

M4 (can) flow/travel/move (through structure) / are mobile
M4 DEP on M3 or near miss
(when voltage/pd is applied)
44

Dr.Ann Mahdy
 4.SOLID STRUCTURE 45

7 (a) (i) 3 [1]

(ii) 70 [1]

(b) Add octane (or other liquid hydrocarbon) (to soot) [1]

COND(on addition of any solvent) filter (to remove insoluble forms of carbon) [1]

(allow to) evaporate or heat or warm or leave in sun(to get crystals of fullerene) [1]

(c) (i) graphite [1]

(ii) delocalised electrons/free electrons/sea of electrons [1]

COND (on electrons) move/mobile/electrons flow [1]

(iii) Any two from: [2]

potassium oxide
potassium hydroxide
potassium carbonate
potassium hydrogencarbonate (bicarbonate)

[Total: 10]

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 Question Answer Mark
Number
1(d) Hydrogen + oxygen → water 1
5.EQUATION

Question Answer Mark

Number
2(b)(i) C + O2 → CO2, ignore state symbols 1

Classified Chemistry
Question Answer Mark
Number
2(c) CaCO3 → CaO + CO2 1

Question
Answer Notes Marks
number
3 d i M1 s

1C - Edexcel
M2 l
M3 aq 2
All three correct = 2 marks
Two correct = 1 mark
One/none correct = 0 marks
Do not award M1 for g or if not
possible to be sure that it is s and
not g
Do not award marks for
abbreviations such as sol / liq

ii M1 blue / purple Allow indigo or violet 1

M2 OH– / hydroxide M1 and M2 independent 1
46

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
4 b M H2 + Cl2 → 2HCl correct formulae = 1 1
1 balancing = 1
5.EQUATION

M Max 1 for symbol or formula error, 1

2 eg HcL, Cl2

Classified Chemistry
Question
Expected Answer Accept Reject Marks
number
5 (a) 2PbS + 3O2 → 2PbO + 2SO2 Multiples and fractions 2

M1 all formulae correct

M2 correct balancing

M2 DEP on M1

1C - Edexcel
IGNORE state symbols

Question
Answer Notes Marks
number
6 b 2 (1) 2 Accept multiples and fractions 1

Question
Answer Notes Marks
number
7 d Ignore state symbols 1
Zn + CuSO4 → Cu + ZnSO4 Accept correct ionic equation with or
without spectator ions
47

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
8 e 4 (1) 2 4 Accept fractions and multiples 1
5.EQUATION

Question
Answer Notes Marks
number
(e) 1

Classified Chemistry
9 NH3 + HNO3 ń NH4NO3

Question Mark
Answer Accept Reject
number s
10 (e) M1 (name) magnesium chloride 1
M2 (formula) MgCl2 accept a correct formula as a
1
product in an equation whether
Penalise inappropriate use of upper or lower case
the equation correct or not
letters or numbers in the wrong place

1C - Edexcel
Question
Answer Accept Reject Marks
number
11 (c) (ii)
1
s l aq g
capital letters

(e) (i) 4Li + O2  2Li2O multiples and halves 2

IGNORE state symbols

M1 formulae
M2 balancing

M2 dep on M1
48

Dr.Ann Mahdy
(ii) 2 (1) (1) multiples and halves 1
 Question
Answer Accept Reject Marks
number
12 (a) magnesium chloride/MgCl2 1

oxygen/O2 carbon dioxide/CO2 1

5.EQUATION

sulfuric (acid)/H2SO4 1
IGNORE hydrogen sulfate

Classified Chemistry
If name and formula given, both must be
correct

(b) Mg + H2O  MgO + H2 1

IGNORE state symbols even if incorrect

Penalise incorrect symbols and failure to

use subscripts

1C - Edexcel
Question
Answer Accept Reject Marks
number
13 (b) 6Li + N2  2Li3N multiples and fractions 2

M1 – all formulae correct

M2 – balanced
M2 dep on M1
IGNORE state symbols even if incorrect
49

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
14 (a) (i) M1 & M2 – any two from: 2
 does not melt/high melting point Ignore general physical properties of
 does not colour the flame metals, eg boiling point
 inert/unreactive / does not burn/react with
5.EQUATION

oxygen/air

(ii) to remove any substance that may affect the colour ignore references to removing 1

Classified Chemistry
impurities
Allow result/flame for colour

(iii) difficult to see the colour produced by the substance Accept flame not hot enough (to 1
(under test) vaporise the sample)
Accept the temperature is not high
enough (to vaporise the sample)
Allow flame is (already) coloured

1C - Edexcel
50

Dr.Ann Mahdy
 Question Answer Mark
Number
1(d) Loss of oxygen / Fe3+ gains electrons / Fe ions gains
electrons / Fe (III) gains oxygen (reject- Fe gains
electrons) 1
6.REDOX

Question
Expected Answer Accept Reject Marks
number
2 (b) (i) Reduced AND oxygen has been removed arguments based on 1
decrease in oxidation
IGNORE It / PbO gains electrons number of Pb/ gain of

Classified Chemistry
Do not penalise molecules electrons by Pb2+ / lead
ions

(ii) M1 Mr (PbO) = 223 446 1

(moles method)
1
M2 n (PbO) = 44.6/223 (=0.2)
1
M3 mass of C = 0.2/2 x 12 = 1.2

1C - Edexcel
(mass ratio method)

M2 446 require 12 / 44.6

M3 44. 6 require 1.2 / 1.2

Calculations with and without use of 106 are

acceptable

mark csq at each stage

Correct final answer with or without working

scores 3
51

Dr.Ann Mahdy
Final answers that may score 2 are:
0.6 / 2.4 / 4.8 / 0.12 / 12
 Question
Answer Notes Marks
number
3 (b) i redox 1
6.REDOX

ii (it/ Al3+/aluminium ions) gain of electron(s) Reject gain of electrons

OR by Al/aluminium 1
Al3+ combines/reacts with electrons Accept decrease in
oxidation state

Classified Chemistry
Ignore/ references to gain
of oxygen

iii C / carbon Accept graphite/coke 1

gain of oxygen / O / O2 DEP on M1 1
OR Ignore forms carbon
reacts/combines/joins/bonds with oxygen monoxide
or O or O2 Ignore references to loss
OR of electrons
reduces water/H2O Accept increase in

1C - Edexcel
oxidation state
Ignore (acts as) reducing
agent

Question
Answer Notes Marks
number

4 a i gains oxygen Accept increase in oxidation number/state 1

Ignore reference to loss of electrons

ii SO2 + H2O → H2SO3 Accept 2SO2 + O2 + 2H2O → 2H2SO4 OR 1

2SO2 + O2 → 2SO3 AND SO3 + H2O → H2SO4
52

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
5 (d) (i) oxidation and reduction occur reject references to oxygen 1
OR
6.REDOX

electron loss and electron gain occur Accept electron transfer

OR
oxidation number increase and decrease Ignore species involved

Classified Chemistry
(ii) M1 – Ag+/silver ion(s) 1

M2 – it gains electron/is reduced M2 DEP on M1 or near miss, e.g. Ag 1

OR
it takes electrons from
Mg/magnesium
(atoms)
OR
its oxidation number decreases
OR
it causes the oxidation number of Mg

1C - Edexcel
to
increase

Question
Answer Notes Marks
number
6 (b) M1 (element oxidised) – carbon / C IGNORE refs to electron 2
loss
M2 (reason) – (it has) gained/ ACCEPT oxidation state/
combined with oxygen / forms number increases
carbon dioxide ACCEPT oxidation state/
number changes from 0
M2 dep on M1 to (+)4
53

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
7 (d) (ii) M1 carbon / C 2

M2 it removes oxygen from the zinc M2 dep on M1

6.REDOX

(oxide) / reject ‘displaces oxygen’

causes zinc ions to gain electrons /
gains
oxygen / is oxidised
Question

Classified Chemistry
Answer Notes Marks
number
8 d M1 identifying reaction 3 or reaction 4 Ignore reactions 5 and 6
2
M2 a correct explanation for either eg

in reaction 3, there is gain of hydrogen Accept increase in oxidation number of H /

changes from 0 to (+)1
Accept decrease in oxidation number of N /
changes from 0 to -3
Ignore references to gain/loss of electrons

1C - Edexcel
in reaction 4, there is gain of oxygen Accept decrease in oxidation number of O/
changes from 0 to -2
Accept increase in oxidation number of N /
changes from -3 to (+)2
Ignore references to gain/loss of electrons

Ignore other explanations

Allow:

Identifying both Reaction 3 and 4 only for 2

marks
Ignore any explanations
54

Dr.Ann Mahdy
9 (b) reaction 1 is redox / Li/2HI reaction [1]
cond reason either oxidation number/state / electron transfer [1]
 7.ELECTROLYES AND EXTRACTION OF METALS 55

Question
Answer Notes Marks
number
1 (b) (i) Ignore “electrons cannot 1
ions fixed/cannot move/not move (when solid)”
mobile/not free (to move) Reject “electrons move (when
OR molten)”
ions not fixed/can Reject refs to atoms /
move/mobile/free (to move) when molecules
molten Ignore particles / covalent
bonding

(ii) Reject bromine in place of 1

bromide, but allow ‘bromine
ions’
because electron(s) lost (from
Ignore refs to number of
bromide)
electrons
Assume "It" refers to bromide
ions

(iii) Ignore state symbols 1

Pb2+ + 2e(-) → Pb
Reject Pb2+ → Pb – 2e(-)
Ignore solid 1
Ignore metallic
silver/grey/shiny (liquid)
No CQ from wrong product in
M1

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 Question
Answer Notes Marks
number
2 a i oxygen / air Accept O 2 but not just O 1
ii iron(III) oxide / ferric oxide Ignore hydrated 1
Accept iron oxide but not ferrous oxide
or iron oxide with an incorrect
oxidation state

Classified Chemistry
b i nail is wet / needs drying 1
OR
rust absorbs water/is wet / rust falls off Not just some of the nail/it falls off
ii bigger/biggest increase/change in mass Accept mass increased more 1
OR Ignore highest mass
mass of rust greater/greatest Ignore just mass increased by 0.3 g
Accept weight in place of mass
iii bigger/biggest increase/change in mass with 1
correct reference to proportion or percentage
iv mass has decreased Accept mass has not increased / 1
should have increased

1C - Edexcel
Accept mass cannot decrease
Accept nail got lighter
7.ELECTROLYES AND EXTRACTION OF METALS

c M1 grease / oil 1
M2 paint 1

Dr.Ann Mahdy
56
 Question
Answer Notes Marks
number
2 d M1 galvanising / sacrificial (protection) Ignore references to anode / cathode 1
M2 zinc more reactive (than iron) Accept zinc higher in (re)activity series 1
OR OR
iron less reactive (than zinc) iron lower in (re)activity series
Must be comparison, eg not just zinc

Classified Chemistry
is reactive without statement that iron
is unreactive
M3 zinc reacts/corrodes/oxidises instead of iron Accept zinc reacts faster than iron 1
OR Accept zinc loses electrons instead
zinc reacts/corrodes/oxidises before iron of/before iron / zinc gives electron(s)
to iron (ions)
Reject zinc rusts
Reject protective layer of zinc oxide
Ignore erodes

Total 11

1C - Edexcel
7.ELECTROLYES AND EXTRACTION OF METALS
57

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
3 a i M1 (A) reduced AND (B) oxidised If first column blank, M1 can be 1
scored from words in second column:
eg reduction is gain of electrons in
2nd column for A scores M2
oxidation is gain of oxygen in 2nd

Classified Chemistry
column for B scores M3
Both above statements would score
M1 as well

If M1 wrong way round, then 0/3

If 1st column has oxidation ×2 or

reduction × 2, then no M1, but it will
sometimes be possible to award
either M2 or M3 for a correct
matching statement.

1C - Edexcel
M2 (A) gain of electrons If species identified, must be correct, 1
7.ELECTROLYES AND EXTRACTION OF METALS

eg not aluminium gains electrons

Ignore reference to loss of oxygen
M3 (B) gain of oxygen Ignore reference to loss of electrons 1
ii M1 Both formulae correct and on correct 1
2O 2– : O 2 + 4e (–) sides of equation
M2 Balancing including electrons 1
Accept electrons lost on LHS
Accept O 2– : O + 2e (–) followed by
2O : O 2
iii electrodes burn /get smaller / decrease (in mass) Ignore erode / corrode / wear / 1
/ have to be replaced damage

Dr.Ann Mahdy
58
 Question
Answer Notes Marks
number
3 a iv M1 coke Ignore coal / carbon 1
Reject other raw materials such as
limestone/haematite
M2 produces heat / exothermic (reaction) M2 independent 1
Accept makes carbon dioxide which

Classified Chemistry
then produces CO/reducing agent

Question
Answer Notes Marks
number
4 (a) An explanation linking the following points:
x green colour spreads throughout liquid ACCEPT dark green at bottom and
x (because of) diffusion light green at top 2

(b) Anode = copper Award 1 mark for both correct

products, but at incorrect electrodes

1C - Edexcel
Cathode = chlorine 2
7.ELECTROLYES AND EXTRACTION OF METALS

(c) 2Cl¯ ˆ Cl2 + 2e ALLOW 2Cl¯ - 2e ˆ Cl2

1 mark for correct species

1 mark for balance 2

Total: 6
59

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

5 a i haematite Ignore iron oxide / formulae 1

ii Al2O3 / Al3+2O2–3 Ignore reactants in equation 1

iii carbon / C Accept graphite

Ignore coke / anthracite 1

Classified Chemistry
(positive/negative) electrode DEP on M1 (including coke or any metal) 1
Accept anode / cathode
Accept references to letting
electrons/electricity/current flow
Accept references to letting
electrons/electricity/current in/out of the
cell/electrolyte
Ignore references to attracting ions
Accept references to conducting electricity
Ignore references to electrolysis

1C - Edexcel
Ignore references to burning or combining with
oxygen
7.ELECTROLYES AND EXTRACTION OF METALS

Ignore references to reduction/oxidation

Question
Answer Notes Marks
number
5 iv oxygen / O2 Accept O 1
Ignore air
production of heat/maintaining temperature DEP on mention of 1
of furnace oxygen/O2/O/air
OR Ignore
formation of reducing agent combustion/oxidation/reaction
/carbon monoxide of carbon/coke
Ignore references to
60

Dr.Ann Mahdy
increasing temperature of
furnace
 Question
Answer Accept Reject Marks
number
6 (a) (i) Any two from: 2
● good conductor of heat
● high melting point
● malleable
Apply list principle

Classified Chemistry
(ii) M1 – ductile 1

M2 – good conductor of electricity 1

Apply list principle
Answers can be given in any order

(b) (i) strong(er) other correct descriptions 1

IGNORE references to density and rusting

lower density / resists corrosion

(ii) IGNORE lighter does not rust 1

1C - Edexcel
greater strength to weight ratio
7.ELECTROLYES AND EXTRACTION OF METALS
61

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

7 a i (hydrated) iron(III) oxide / ferric oxide Accept (hydrated) iron oxide 1

Reject iron with other oxidation states
Ignore formulae even if incorrect

ii no water / moisture Accept drying agent absorbs water 1

Classified Chemistry
Prevents water from reaching nail
reacting with nail
Reject no air/oxygen

iii to keep air/oxygen out (of water) Accept to keep air/oxygen from 1
dissolving in water/away from nail

b i galvanising Ignore sacrificial protection 1

ii zinc more reactive than iron / above iron in Accept converse statements

1C - Edexcel
reactivity series / better reducing agent than iron /
loses electrons more readily
7.ELECTROLYES AND EXTRACTION OF METALS

zinc reacts/corrodes/oxidises (instead of iron) Reject zinc rusts

Accept zinc reacts first/before iron
Zn → Zn2+ + 2e (occurs) 4
Fe → Fe2+ + 2e does not occur
OR
Fe2+ + 2e → Fe (occurs)
If neither M3 nor M4 given, award 1
mark for Zn + Fe2+ → Zn2+ + Fe
62

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

7 c i oxidation Ignore ionisation 1

loss of electron(s) Accept increase in oxidation number 1
M2 DEP on M1 or near miss
No ECF from reduction

ii copper ions are formed (at rod) Accept Cu2+ for copper ions and Cu for 1

Classified Chemistry
AND copper atoms
reduced / removed (from solution) / converted to Reject references to displacement
(copper) atoms formed (at nail)
concentration/number/amount of copper ions Accept copper sulfate in place of 1
remains constant copper ions

(Total for Question 3 = 12 marks)

Question
Answer Notes Marks

1C - Edexcel
number
8 b i B (the products are both elements) 1
7.ELECTROLYES AND EXTRACTION OF METALS

ii electrons on wrong side / should be on right Accept + in front of electrons (should be —) 1

/should be – 2e–
2Br should be Br2 Accept product is shown as a bromine atom 1
/ should be shown as a bromine molecule
Equation correctly rewritten scores both marks

iii ions stop moving / ions not free to move Ignore liquid becomes solid / no free ions 1
OR
electrons stop moving (through wires) Accept electric current in place of electrons
Reject implication that electrons stop flowing
through liquid
63

Dr.Ann Mahdy
7.ELECTROLYES AND EXTRACTION OF METALS 64

Question Answer Mark

Number
9(a) 1 Oxygen
2 Water 2

Question Answer Mark

Number
9(b) Iron oxide / rust 1

Question Answer Mark

Number
9(c) 1 mark for each, maximum 2
x Oil
x grease / polish
x paint
x plastic
x zinc
x Accept chrome / chromium
Reject copper / magnesium 2

Question Answer Mark

Number
10(e)(i) Aluminium too reactive / more reactive than carbon
/ accept Al very high in the reactivity series 1

Question Answer Mark

Number
10(e)(ii) Any suitable use, eg airplanes PLUS
Property must be related, eg low density
eg
Specified transport - low density (not light)
Cooking foil/drink cans - easily moulded / malleable
Power cables - good conductor of electricity
Window frames / cars - does not corrode

Credit any other suitable Answers 2

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 Question
Answer Notes Marks
number
11 a i M1 (hydrated) iron(III) oxide / Fe2O3 Allow (hydrated) iron oxide and 1
Fe2O3.xH2O

ii M1 oxygen / O2 Allow air 1

Do not accept O
M2 water / H2O Accept poorly written formulae such 1

Classified Chemistry
as H2O and O2
Accept phonetic spellings
Answers can be in either order
Reject salt / acid - eg salt water does
not score

b M1 cross in box 4 (oxidation) 1

c i M1 Zinc / Zn Accept phonetic spellings 1

1C - Edexcel
ii M1 cross in box 2 (Bucket) 1
7.ELECTROLYES AND EXTRACTION OF METALS

d M1 oiling / greasing / painting / covering with plastic / Any two for 1 each 2
M2 coating with tin or named metal (aluminium or Ignore sacrificial protection and
below) in reactivity series / attaching magnesium galvanising and alloying
or zinc blocks (to ships)

Total 8 marks
65

Dr.Ann Mahdy
 7.ELECTROLYES AND EXTRACTION OF METALS 66

Question
Answer Notes Marks
number
12 (a) (i) electrolysis 1

(iv) cryolite Accept Na3AlF6 1

solvent (for alumina) Reject to lower melting or 1
boiling point of alumina /
OR aluminium oxide / aluminium
Ignore refs to boiling point of
to lower operating temperature / mixture / electrolyte
to lower melting point of mixture / Accept to reduce (heat)
electrolyte energy requirement
Accept to increase
conductivity of electrolyte
Ignore references to boiling
point
Reject acts as catalyst
M2 indep of M1

12 (c) (iv) low density / high strength to Ignore light 1

weight ratio Accept lightweight / not dense

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 Question
Answer Accept Reject Marks
number
13 (a) M1 (negative electrode) – graphite carbon 2

M2 (positive electrode) – graphite carbon

(c) M1 reduction redox for M1 only 1

M2 (it/aluminium ions/Al3+) gain of electron(s) reacts with/combines with Al/aluminium gains 1

IGNORE references to loss of oxygen decrease in oxidation electrons

Classified Chemistry
number/oxidation number
M2 dep on M1 changes from +3 to 0
(e) Any two from: 2

M1 malleable easy to shape/easy to

bend/easy to extrude bend

M2 low density

M3 does not react with food/drink(s) non-toxic/does not corrode

1C - Edexcel
IGNORE light(er)/high strength to weight
7.ELECTROLYES AND EXTRACTION OF METALS

ratio/references to cost/lightweight/does not rust

67

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
14 (c) (i) C + O2 → CO2 1

(ii) C (neutralisation) 1

(d) (i) M1 oxygen accept ‘air’ 2

M2 water accept ‘moisture’ / ‘water vapour’

Classified Chemistry
ignore ‘steam’
accept answers in either order

(ii) prevents oxygen/water from coming accept refs to acting as a barrier 1

into contact with the iron

(e) (i) galvanising ignore ‘sacrificial protection’ 1

1C - Edexcel
(ii) M1 zinc is more reactive than iron / ignore ‘sacrificial protection’ 2
7.ELECTROLYES AND EXTRACTION OF METALS

loses
electrons more readily
accept ‘reacts (with oxygen/water) in preference (to
M2 (and therefore) corrodes in the iron)’
preference (to accept refs to zinc converting iron(II) ions to iron
the iron) (atoms)
reject ‘zinc rusts’ for M2

(f) (aluminium/it) is too reactive / more accept ‘carbon is less reactive than aluminium’ 1
(i) reactive than carbon / above carbon in accept ‘the temperature required is too high’
the reactivity series ignore refs to carbon monoxide
68

Dr.Ann Mahdy
energy costs are too great / electricity allow ‘it is cheaper to use the blast furnace’ 1
(ii) is expensive ignore refs to iron being below carbon in the
reactivity series
 Question
Answer Notes Marks
number
15 (b) (i) 2 2 (1) (1) accept halves and multiples 1

(ii) B (HCl(aq)) 1

(c) (i) aq aq aq s Do not accept words eg aqueous 1

Classified Chemistry
(ii) M1 filter (off the precipitate) allow ‘decant’ 3

M2 wash (with distilled/deionised/pure reject refs to crystallisation for M2 and M3

water)
allow ‘heat it’
M3 dry in a warm oven / leave to dry /
dry with filter paper

1C - Edexcel
16 C
7.ELECTROLYES AND EXTRACTION OF METALS

17 D
18 A
19 B 1

20 B
69

Dr.Ann Mahdy
 7.ELECTROLYES AND EXTRACTION OF METALS 70

21 (b) coolant / solvent / hydroelectric power [1]

allow for cooling / to cool
allow specific reactions e.g. making sulfuric acid / making ethanol
allow: for washing or cleaning if specific industrial process mentioned
allow for agriculture / for growing crops (on a large scale) / brewing
ignore for cooking / for drinking / for power (unqualified) / for watering plants / for cooling food

(c) substance OR liquid which dissolves another (substance) /

substance which does the dissolving [1]
ignore it dissolves / it is a liquid / names of solvents

22 (a) (i) correct points (each within one small square) [2]
–1 mark for each incorrect point
smooth curve [1]
ignore: continuation of curve at either end

(ii) 75 oC / the highest [1]

allow: values above 75 oC

(iii) the higher the temperature the faster the reaction / speed greater at higher
temperature [1]
allow: the higher the temperature the faster the word disappear
ignore: gets faster without qualification / faster with temperature / higher temperature
increases rate of collisions / it takes less time the higher the temperature

(b) increases / gets faster [1]

not: goes fast

(c) (i) sodium chloride [1]

apply: listing if extra species

(ii) VI / vi / 6 / six [1]

(iii) forest death / acidifies lakes or rivers / kills fish / plant in lakes or rivers /
slows crop growth / leaches harmful minerals from soil / erodes (or corrodes) buildings
(or metals) / kills corals [1]
ignore: acid rain / kills animals / kills plants or fish in sea

(iv) 2nd box down ticked (calcium oxide) [1]

(v) magnesium gains oxygen / increases its oxidation number / gets oxidised [1]
allow: loses electrons / Mg gets oxidised
sulfur dioxide loses oxygen / decreases its oxidation number; [1]
allow: gains electrons / SO2 gets reduced
ignore: repeating what is in the equation
note: oxidation and reduction occurs together = 1

[Total: 12]

23 (b) ⇌ [1]

6H2O on right [1]

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 8.ACID , BASES AND SALT PREPARATION 71

Question Answer Mark

Number
1 (c) Blue / purple
(solution made is) alkaline / (contains) hydroxide
ions OH- / not just ‘alkali metal’
pH 11→14 (any in range) 2

Question
Answer Notes Marks
number
2 (a) (i) silver chloride Accept silver(I) chloride 1

(ii) AgNO3 + NaCl → AgCl + Reactants = 1 1

NaNO3 Products = 1 1
Award 1 mark if all formulae
correct but equation
unbalanced
Accept a correct ionic
equation for 2 marks - Ag+ +
Cl– → AgCl
Ag+ + Cl– → scores M1 (but
only with arrow)

(b) s for PbSO4 and aq for other three 1

species

(c) (i) (dilute) nitric acid / HNO3 Accept sodium carbonate / 1

sodium hydroxide / NaOH sodium hydrogencarbonate / 1
sodium bicarbonate
Award 1 mark if both
substances correctly identified
but written in the wrong order
If name and formula given,
both must be correct.

(ii) 22.30 Penalise missing zeroes once 1

3.60 only 1
18.70 Award 1 for 2 correct 1
readings in wrong order
M3 CQ on M1 and M2

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 8.ACID , BASES AND SALT PREPARATION 72

Question
Answer Notes Marks
number
2 (d) (i) ticks in boxes under columns 2 and 1
4

(ii) 22.5(0) + 22.6(0) CQ on candidate's ticked 1

2 results – if average of
22.55 (cm3) different results, then 0 1
If ticked results other than
the correct ones, then final
answer must be to 2 dp to
score M2, but no penalty for
missing trailing zeroes
Average of 1 result scores 0
Correct answer with no
working scores 2 marks

2 (e) filter Allow decant / pour off water 1

leave crystals to dry / dab Ignore washing 1
crystals with filter paper/kitchen Allow “leave to evaporate (rest
towel / warm (in oven) of) water / leave to evaporate
to dryness” for 2 marks
If filter / decant / pour off
water mark not scored, then
marks can be awarded as
follows:
M1 leave in warm
place/sun/on window ledge /
heat or warm (in oven)
M2 to evaporate/remove
water/until dry
No marks can be awarded if
there is a statement about
using strong heating or a
bunsen burner

Question
Answer Notes Marks
number
3 (c) (i) red Allow pink 1

(ii) more than one colour in acid / Do not accept just more than 1
indicates pH / shows strongly or one colour
weakly acidic / shows how acidic
the water is

(iii) any value in range 1 – 6.9 1

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 Questio
n
Answer Notes Marks
numbe
r
4 e M1 Corrosive / burns / damages skin or eyes Ignore harmful / irritant / toxic / poisonous 1
M2 Wear eye protection eg goggles or mask Allow tongs / tweezers if reference to cotton 1
/ gloves / place bung in the end of the wool

Classified Chemistry
tube / use of fume cupboard Ignore lab coats
M1 and M2 are independent

Question
Answer Notes Marks
number
5 a i M1 bubbles / fizzing / effervescence Allow just gas (given off) 1
OR Ignore wrongly named gas
solid/magnesium disappears/dissolves
8.ACID , BASES AND SALT PREPARATION

OR

1C - Edexcel
flask gets warm Allow temperature increases but not heat
produced

ii M1 magnesium chloride / MgCl2 Accept phonetic spellings 1

Accept poorly written formulae such as
MGCl2 and MgCL2

Question
Answer Notes Marks
number
6 d ii M1 blue / purple Allow indigo or violet 1
M2 OH– / hydroxide M1 and M2 independent 1
73

Dr.Ann Mahdy
 Question
Expected Answer Accept Reject Marks
number
7 (a) M1 precipitate of barium sulfate sulphate for incorrect name of ppt. 1
sulfate
insoluble barium
sulphate / BaSO4

no (visible)
M2 no precipitate

Classified Chemistry
change
1
solution (formed)

M3 precipitate of calcium sulfate sulphate for incorrect name of ppt. 1

sulfate
IGNORE colours insoluble calcium
sulfate / CaSO4
penalise incorrect extra observations (e.g.
effervescence) ONCE only
8.ACID , BASES AND SALT PREPARATION

For M1 and M3 only:

1C - Edexcel
if only precipitate appears twice (with no names),
penalise missing names once only

if only names correct (with no precipitates), penalise

omission of precipitate once only
74

Dr.Ann Mahdy
 Question
Expected Answer Accept Reject Marks
number
7 (b) aq aq s aq 1

(c) (i) obtain the lead(II) bromide/the residue/the solid separate the solid 1
and liquid
OR

remove the liquid/solution/potassium nitrate/water

Classified Chemistry
(ii) to wash away/remove the (remaining) potassium wash away / make the mixture pure 1
nitrate / lead(II) nitrate / potassium bromide / remove
solution (remaining
soluble) impurities
IGNORE clean to make it pure

(iii) distilled water is pure / does not contain (dissolved) reverse argument any suggestion that the 1
impurities / ions / substances / compounds / other for tap water water / impurities react
8.ACID , BASES AND SALT PREPARATION

chemicals (that would contaminate the lead(II)

1C - Edexcel
bromide) / residue / solid)

IGNORE elements
IGNORE references to distilled water being cleaner
(ORA)

(iv) to evaporate the water / to dry (the solid/crystals) / to avoid to evaporate the 1
increase rate of evaporation (of water) decomposition (if potassium nitrate /
heated strongly) solution
IGNORE liquid any reference to
crystallisation
75

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
9 (a) An explanation linking the following points:
x more precipitate as more lead(II) nitrate present (to react
with potassium iodide)
x but eventually all potassium iodide used up / lead(II) nitrate
becomes in excess / the reaction finishes 2

(b) (i) correct point circled (at 12cm3 of lead(II) nitrate added) ACCEPT any way in which this point is 1

Classified Chemistry
indicated

(ii) Any two of the following pairs of statements: ACCEPT reasonable alternatives, as
x not left long enough long as they explain why the height is
x therefore precipitate / solid not fully settled too high
OR
x too much potassium iodide added
x so more precipitate made
OR
8.ACID , BASES AND SALT PREPARATION

x tube not vertical when precipitate was settling

1C - Edexcel
x so precipitate not level in the tube max 4

(c) (i) 1.5 ± 0.1 (cm) ACCEPT 0.8 cm (for candidates who 1
use their own ruler)

(ii) 3.7 – 3.8 (cm3) ALLOW consequential on answer to 1

(c)(i)

Total: 9
77

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
10 (a) i cross in box A (zinc sulfate) 1

ii Apply list principle - 3 crosses = max 1 1

cross in box B (iron)
4 or 5 crosses = 0 marks 1
cross in box C (magnesium)

Question
Answer Notes Marks
number

Classified Chemistry
11 a reference to line/curve/temperature Ignore reference to correlation 1
/graph/it Ignore has not reached zero / x-axis
AND Ignore does not become
not reached minimum / not constant / not
level
/not horizontal /still falling
/decreasing/changing

b (better) insulator (than glass) Accept equivalents such as prevents heat from 1
8.ACID , BASES AND SALT PREPARATION

OR entering / keeps out heat better

1C - Edexcel
poor conductor (of heat) Allow stops heat escaping / traps heat
Reject references to keeping temperature constant
Ignore references to breaking glass

c i effervescence / fizzing / bubbles Accept carbon dioxide gas 1

OR Accept gas given off/evolved/formed
colourless solution/liquid formed Ignore identity of gas
Accept solid disappears/dissolves
Ignore hissing and other sounds

ii Neutralisation Accept acid-base / acid-alkali 1

endothermic M1 and M2 independent 1

Accept answers in either order
78

Dr.Ann Mahdy
Do not penalise contradictions such as exothermic
and endothermic – this answer is worth 1 mark
 Question
Answer Notes Marks
number

12 (a) i beaker Ignore qualifiers such as measuring 1

/ graduated / 250 cm3

ii Pipette Ignore qualifiers such as measuring 1

/ graduated / 25 cm3

Classified Chemistry
iii colour change is gradual /not Ignore reference to many colours 1
sharp/not defined
OR
end point not sharp/defined/accurate

methyl orange / phenolphthalein / Accept other correct indicators 1

litmus Ignore reference to pH meter
Reject litmus paper
Ignore named colours and colour changes
8.ACID , BASES AND SALT PREPARATION

iv (measures) only one volume / fixed Ignore reference to accuracy / size 1

1C - Edexcel
volume / 25 cm3 Accept reverse arguments based on suitability of
has only one graduation mark burette, eg burette can deliver/measure any
OR volume
cannot deliver (measured) variable
volume
OR
volume required is not known
OR
cannot be controlled / hard to control
79

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

12 (b) (after) 22.60 1

(before) 2.75 1

Classified Chemistry
(added) 19.85 CQ on before and after readings 1
Award 1 for before and after
values both correct but in wrong
order
All values must be to 2 dp
Penalise answers to other than 2
dp once only
8.ACID , BASES AND SALT PREPARATION

Question

1C - Edexcel
Answer Notes Marks
number

12 (c) i ticks in columns 3 and 4 1

ii 23.35 + 23.45 CQ on ticked results 1

2 If no results ticked, award M1 if
only columns 3 and 4 averaged
If only 1 result ticked, then no
marks can be awarded in (c)
23.4(0) CQ on results averaged 1
Answer should be to 2 dp, except
that trailing zero not needed
Correct final answer without
80

Dr.Ann Mahdy
working scores 2
 Question
Answer Notes Marks
number

12 (d) i divide/÷ by 1000 (not by Accept 0.0500 × 23.60 (= 1

100) 0.00118 mol)
OR 1000
convert volume/cm3 to dm3 Accept divide (final) answer by 10
OR
use 1000 instead of 100

Classified Chemistry
ii multiply/× (amount of H2SO4) Accept 0.(0)0118 × 2 (= 1
by 2 (not divide by 2) 0.0(0)236 mol)
Accept any other number in place
of 0.0(0)118
Accept multiply (final) answer by 4

iii divide by 25.0 (not by 23.60) Accept 0.00590 × 1000 (= 0.236 1

OR mol)
divide by volume of KOH (not 25.0
by volume of H2SO4) Accept any other number in place
8.ACID , BASES AND SALT PREPARATION

1C - Edexcel
OR of 0.00590
use 25.0/volume of KOH
instead of 23.60/volume of
H2SO4
Must be positive statement about
correction needed, e.g. in iii,
ignore statement about volume of
H2SO4 should not have been used
Total 14
81

Dr.Ann Mahdy
 Question
Answer Accept Reject Marks
number
13 (a) (i) measuring cylinder 1

(ii) M1 44 answers in other 1

correct units, e.g.
0.044 dm3 1
M2 cm3
ml

Classified Chemistry
(iii) 1

M2 0.00044(0)
0.0004 1
0.44 for 1 mark only
Mark csq on answer to (a)(ii)
correct answer with no
working for 2 marks
8.ACID , BASES AND SALT PREPARATION

1C - Edexcel
82

Dr.Ann Mahdy
 Question
Answer Accept Reject Marks
number
14 (a) (produces) most heat/energy per gram / per unit highest temperature rise per gram / per 1
mass per unit mass amount
most energy for smallest number of
grams / mass

Classified Chemistry
(b) (produces) most heat/energy per mole/per highest temperature rise per mole / 1
molecule /per amount per molecule
most energy for smallest number of
moles / molecules / amount

(c) Any two from: 2

● heat/energy losses (e.g. by convection, by ● non-standard conditions
conduction, to air, to surroundings)
● incomplete combustion
8.ACID , BASES AND SALT PREPARATION

● evaporation of water

1C - Edexcel
● copper / can / beaker / thermometer
/apparatus
absorbs heat
● flame moves around because of draughts
83

Dr.Ann Mahdy
 Question
Answer Accept Reject Marks
number
15 (c) (iii)
1
M1 turns blue
IGNORE purple
1
M2 alkaline solution formed/alkali formed/hydroxide OH— for hydroxide ions
ions pH is greater than 7

Classified Chemistry
formed/LiOH is an alkali/LiOH forms hydroxide
ions

IGNORE references to lithium hydroxide is a metal

hydroxide
M2 dep on M1 correct or missing
8.ACID , BASES AND SALT PREPARATION

1C - Edexcel
84

Dr.Ann Mahdy
 Question
Answer Accept Reject Marks
number
16 (a) to increase the rate/speed to overcome the activation Answers referring to 1
(of the reaction) energy/to provide activation copper instead of
energy (for the reaction) copper(II) oxide

IGNORE to start the reaction/to provide

Classified Chemistry
energy/references to the copper(II) oxide
will not react without heat / to make it
dissolve faster / to give particles more
energy

(b) it stops disappearing stops dissolving 1

OR
precipitate/ppt any colour other than
there is a (black) suspension/solid
black
8.ACID , BASES AND SALT PREPARATION

/copper(II) oxide

1C - Edexcel
OR
the mixture/it turns cloudy/black
IGNORE crystals

(c) to remove (unreacted/excess) copper(II) to remove (unreacted/excess) to separate copper(II) 1

oxide solid oxide from sulfuric
IGNORE references to impurities/crystals acid
to obtain a solution (of
copper(II) sulfate)
(d) copper(II) sulfate/the crystals are less reverse argument references to freezing 1
soluble in cold water (than in hot water) ions join together (to form a
OR solubility decreases with temperature lattice)
IGNORE reference to water evaporating ionic lattice forms
85

Dr.Ann Mahdy
 (e) blue any colour other than 1
blue
IGNORE shades of colour

(f) on filter paper/kitchen towel/tissue paper OWTTE heat / hot oven 1

OR
leave / in a warm place / in the sun / on desiccator
a radiator / near a window / in a
(warm/drying) oven

Classified Chemistry
(Total marks for Question 4 = 6 marks)

u
Q estion
Answer Accept Reject Marks
number
17 (a) (i) 13(.0) 1

(ii) 1.4 1
8.ACID , BASES AND SALT PREPARATION

1C - Edexcel
(iii) 25(.0) 1

(b) indigo 1

red 1

(c) NaOH + HCl  NaCl + H2O H+ + OH─  H2O 1

IGNORE state symbols even if incorrect

(Total marks for u

Q estion 6 = 6 marks)
86

Dr.Ann Mahdy
 Question
Answer Accept Reject Marks
number
18 (c) (i) l aq g 1

(ii) M1 – any number from 8 to 14 1

M2 – LiOH/lithium hydroxide is a base/alkali ammonia / metal 1

OR hydroxides / Group 1

Classified Chemistry
hydroxides are
hydroxide ions/OH— formed/present
bases/alkalis
8.ACID , BASES AND SALT PREPARATION

1C - Edexcel
87

Dr.Ann Mahdy
 Question
Answer Accept Reject Marks
number
19 (a) large hydrocarbons/alkanes/molecules become (large) hydrocarbons or alkanes or references 1
small ones molecules become smaller ones to polymers
IGNORE references to forming alkenes/ethene/
long chains become short chains
more useful molecules

Classified Chemistry
(b) M1 – (add to) bromine (water)/Br2 (acidified) potassium 1
IGNORE Br manganate(VII)

M2 – (bromine) decolourised/turns colourless 1

decolourised/turns colourless
IGNORE starting colour and clear
M2 dep on M1, but can be scored for a near
miss in M1,eg Br or bromide (water)
8.ACID , BASES AND SALT PREPARATION

1C - Edexcel
(c) M1 – (catalyst) silica / silicon dioxide / alumina correct formula 1
/ aluminium oxide aluminosilicate / zeolite

N.B. if both name and formula given, mark the

name only
any value or range within this range 1
M2 – 600-700 ºC
equivalent temperatures in Kelvin

(Total marks for Question 11 = 5 marks)

88

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
20 a mix / add / react (the two) solutions / salts Ignore references to volumes
together
stir Accept swirl 4
filter Accept description of filtration
wash (with water)
suitable method of drying eg warm / heat / place in oven / leave on
window ledge / leave to dry / dry with filter

Classified Chemistry
paper or kitchen towel
Not just dry
Any four above for 1 mark each
If M3 not scored then M4 and M5 cannot be
awarded
If description of evaporation of solution, then
M4 and M5 cannot be awarded
identifying two suitable pieces of apparatus Any two of 1
 beaker / flask / test tube (for mixing)
 (glass) rod (for stirring)
8.ACID , BASES AND SALT PREPARATION

 (filter) funnel/paper (for separation)

1C - Edexcel
Reference to filter paper or filter funnel scores
M3 and counts as one of M6
If any other substance added, then MAX 4
89

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

21 a pipette 1

b B (pink to colourless) 1

Classified Chemistry
c correct reference to one of these: Examples: 1
 number of colours phenolphthalein has only two colours / only one
colour change
/ negative statement eg does not have a range of
colours
 end point/colour change (accept neutral / UI has several colours/more than one colour
point) change
8.ACID , BASES AND SALT PREPARATION

sharp / definite / sudden / quick / not gradual /

1C - Edexcel
needs only one drop
/ converse for UI

d M1 (after) 24.15 (only this 3

answer) Award 1 mark for both burette readings correct but
in wrong order
M2 (before) 2.30 (only this
answer)
CQ on after and before readings
M3 (added) 21.85
In M3, penalise answer not to 2 dp unless penalty
already applied in M2
90

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

21 e i ticks in columns 2 and 4 1

ii M1 26.30 + 26.40 CQ on ticked results 2

2 If no results ticked, award M1 only if columns 2 and 4 averaged
If only one result ticked, no marks can be awarded in (e)

Classified Chemistry
M2 26.35 CQ on results averaged
Answer must be to 2 dp
M2 subsumes M1
8.ACID , BASES AND SALT PREPARATION

1C - Edexcel
91

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
22 (a) all of the sodium chloride has reacted Accept no more sodium chloride left (to 1
react)
/ the sodium chloride has been used up
Accept sodium chloride is the limiting reagent
reject all reactants used up
Ignore reaction has stopped/is complete

M1 & M2 - all points correctly plotted 2

Classified Chemistry
(b) (i) deduct one mark for each point incorrectly
plotted
1
M3 – two straight lines drawn
lines must be drawn with the aid of a ruler
first line does not need to go through origin
second line must be horizontal 1

M4 – lines intersect
8.ACID , BASES AND SALT PREPARATION

M4 dep on M3

1C - Edexcel
(ii) circle drawn around point (2.5,10) 1

(iii) A (the precipitate was not allowed to settle 1

before its height was measured)

(iv) no precipitate is produced when no lead(II) Accept the height of precipitate is (directly) 1
nitrate is added proportional to the volume of lead(II) nitrate
(added)

Accept the two variables (plotted) are

(directly) proportional (to one another) 1
92

Dr.Ann Mahdy
 Ignore no reaction / reaction not started

(v) 7 (cm3) accept any value between 6.8 and 7.2

Total 9 marks

Question
Answer Notes Marks

Classified Chemistry
number
23 (a) (i) Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g) 2

M1 – all formulae correct and equation balanced

M2 – state symbols correct

M2 can be awarded for near misses on
formulae, e.g. ZnCl and H

accept upper case letters for state

8.ACID , BASES AND SALT PREPARATION

1C - Edexcel
symbols

(b) M1 bubbles/fizzing/effervescence accept gas given off 2

ignore hydrogen given off

M2 zinc/solid gets smaller/disappears accept zinc/solid dissolves / (final)

solution is colourless
reject zinc melts and other Group 1
observations, eg floats / moves across
surface

Ignore references to heat and

temperature change
93

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
23 (c) (i)

Classified Chemistry
M1 – all four burette readings correct Ignore trailing zeroes for M1 and
M2
M2 – subtractions correct
M2 CSQ on burette readings given
M3 – all six values in table given to 2 decimal places in table
8.ACID , BASES AND SALT PREPARATION

(ii) M1 – (because) the volume/amount of acid required has Mark independently 1

1C - Edexcel
doubled
M2 – the concentration is half / 0.37 (mol dm–3) 1

OR

M1 for use of an expression such as V1c1 = V2c2 accept either a calculation or a

description
M2 for indicating how c2 can be calculated (e.g. because
V1 , c1 , and V2 are known) / for an answer of 0.37 (mol
–3
dm )
94

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
24 (a) measuring cylinder/measuring jug accept burette/pipette 1

(b) no more bubbles/fizzing/effervescence/gas given 1

off
OR allow solid remains in the solution
solid/zinc carbonate can be seen in the beaker
OR

Classified Chemistry
the solid/zinc carbonate stops
disappearing/dissolving
OR
a suspension (of zinc carbonate) forms ignore the reaction stops
OR
the liquid turns cloudy
(c) filtration accept filtering 1
accept centrifuging
(d) M1 – heat/boil to partially evaporate (the accept to remove some of the water 1
water) accept heat to form a saturated/concentrated
8.ACID , BASES AND SALT PREPARATION

solution

1C - Edexcel
/ heat until crystals form on (cold) glass rod /
heat until crystals (just start to) form
If evaporated to dryness then award no marks for
whole question

M2 – leave to crystallise / leave until crystals accept leave to cool 1

form
accept pour off/decant (excess) liquid 1
M3 – filter (to remove excess liquid)
e.g. use filter paper/blotting paper/kitchen towel 1
M4 – appropriate method of drying crystals / leave in (warm) oven/drying oven
Accept leave to dry
Do not accept hot oven/heat with a Bunsen flame
95

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
25 (a) 3

Classified Chemistry
M1 & M2 all points correctly plotted to deduct one mark for each incorrectly plotted point
8.ACID , BASES AND SALT PREPARATION

1C - Edexcel
nearest gridline do not penalise missing (0, 0)
if points are not visible, but graph goes through
that point, then do not penalise
M3 suitable curve of best fit, from the
origin
96

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
(b) (i) 25 (cm3) accept anomalous point based on graph 1
drawn

(ii) M1 the volumes (of gas) are the same accept ‘no more gas is being 2
produced/collected (after 35 cm3)’

Classified Chemistry
M2 therefore the reaction has finished / reject ‘all of the reactants have reacted’
all of the solid/MgCO3 has reacted / the reject ‘all of the acid has reacted’
solid/MgCO3 has been used up ignore refs to MgCO3 dissolving
accept refs to MgCO3 being limiting reagent

(iii) value correctly read to nearest gridline 1

from candidate’s graph
8.ACID , BASES AND SALT PREPARATION

1C - Edexcel
(iv) value correctly read to nearest gridline 1
from candidate’s graph

Question
Answer Notes Marks
number
26 (d) (i) SO2 + H2O → H2SO3 accept SO2 + H2O + ½O2 → H2SO4 1
allow products shown as correct ions

(ii) M1 (Universal Indicator turns) accept ‘red’ 2

orange/yellow
allow ‘contains sulfurous / sulfuric acid’
97

M2 (the solution/it) is acidic / contains

Dr.Ann Mahdy
hydrogen
ions / contains H+ ions
 Question
Answer Notes Marks
number
27 (a) M1 chromate (ions) are negative accept ‘anions’ 2

M2 so they are attracted/move towards accept ‘anode’

positive electrode/electrode B

Classified Chemistry
Question
Answer Notes Marks
number
28 (a) (ii) M1 any value greater than 7 ACCEPT “greater than 2
7”

M2 hydroxide ions/OH- are present / ACCEPT metal

calcium hydroxide/Ca(OH)2 is an alkali hydroxides are
/ calcium hydroxide/Ca(OH)2 is a base alkalis/bases
8.ACID , BASES AND SALT PREPARATION

1C - Edexcel
IGNORE hydroxides
are alkalis/bases
M2 dep on correct or missing M1 IGNORE calcium is an
alkali metal
98

Dr.Ann Mahdy
8.ACID , BASES AND SALT PREPARATION 99

Question
Answer Notes Marks
number
29 (a) (i) Q R S P 2

M1 Q and P correct

M2 R and S correct

(ii) M1 magnesium chloride ACCEPT correct 2

formulae
M2 hydrogen IGNORE incorrect
formulae
M1 and M2 can be in either order

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 Question
Answer Notes Marks
number

30 (a) (i) 5
M1 sodium hydroxide / NaOH (solution) Accept sodium carbonate / Na2CO3

M2 pipette used to transfer (25 cm3 of) sodium Accept sodium carbonate / Na2CO3
hydroxide / alkali to a conical flask M2 subsumes M1 if sodium hydroxide

Classified Chemistry
/sodium carbonate mentioned

M3 place (sulfuric) acid in burette

M4 add indicator (to conical flask) Accept suitable named indicator

Reject Universal Indicator

M5 add acid (from burette to conical flask) until M5 subsumes M3 if burette mentioned
indicator changes colour
8.ACID , BASES AND SALT PREPARATION

If named indicator is given any final

1C - Edexcel
colour given must be correct

Alkali in burette and acid in

pipette/conical flask can score max 3

(a) (ii) M1 (after) 23.20 3

Award 1 mark for both readings correct
M2 (before) 3.55 but in wrong order

M3 (added) 19.65 M3 CQ on (M1 – M2)

Penalise an answer not to 2 dp once

only eg 23.2 3.5 19.7 scores 1
100

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

30 (b) M1 name of soluble barium compound eg barium chloride / barium nitrate / 5

barium hydroxide
accept correct formulae

M2 mix/react/add (solutions/reactants) together OWTTE M2 DEP on M1

Classified Chemistry
M3 filter Accept decant / pour off liquid

M4 wash solid/residue/barium sulfate (with

distilled/deionised water) M4 and M5 DEP on M3

If method refers to, or infers use of,

filtrate / solution / crystallisation
then cannot score M4, M5
8.ACID , BASES AND SALT PREPARATION

1C - Edexcel
M5 appropriate method of drying solid
eg leave it (to dry) / leave in a warm place / Not just dry it
place in an oven / place in desiccator / heat it / Accept leave on a window ledge
dry with absorbent paper (eg kitchen/filter/blotting)
M3 M4 M5 can be scored even if
preceding method invalid eg barium
+ sodium sulfate

(Total for Question 8 = 13 marks)

31 (a) breakdown (of substance / electrolyte) by electricity / splitting up of substance by electricity /

decomposition by electricity [1]
allow current / voltage for electricity
101

Dr.Ann Mahdy
ignore separation by electricity / division by electricity
note idea of breakdown AND idea of current / electricity for the mark
9.Calculations 102

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 103

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 104

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 105

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 106

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 107

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 108

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 109

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 110

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 111

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 112

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 113

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 114

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 115

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 116

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 117

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 118

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 119

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 120

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 121

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 122

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 123

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 124

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 125

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 126

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 127

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 128

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 129

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 130

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 131

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9.Calculations 132

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 133

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 134

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 135

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9.Calculations 136

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 137

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 138

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 139

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 140

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 141

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 142

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 143

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 144

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 145

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9.Calculations 146

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9.Calculations 147

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9.Calculations 148

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 149

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 150

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 151

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 152

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 153

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 154

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 155

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9.Calculations 156

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 157

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 158

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 159

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 160

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 161

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9.Calculations 162

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

9.Calculations 163

Classified Chemistry 1C - Edexcel Dr.Ann Mahdy

 Question
Expected Answer Accept Reject Marks
number
1 (a)
4
Proton Neutron Electron

relative 1 1 +1 − 1 / one
mass
1.Atomic Theory

relative 0 -1 Zero
charge minus one /negative

Classified Chemistry
1 mark for each correct answer
(b) (i) Protons AND electrons = 1 one 1
neutrons = 2 two 1

(ii) atoms of the same element atoms with same molecules / 1

atomic number / compounds for first
number of protons / mark only
proton number 1
with different masses

2C - Edexcel
Ignore references to electrons with different mass different relative
numbers / different atomic masses for
numbers of neutrons / second mark only
different neutron
numbers
1 (c) ((79 x 50.7) + (81 x 49.3))/100
OR

(79 x 0.50.7) + (81 x 0.493) 1

1
= 79.99 Correct answer on its
Allow 1 mark for a single transcription error (e.g. own scores 2
164

Dr.Ann Mahdy
43.9 instead of 49.3)
Ignore units such as grams
Total 10
 Question
Answer Notes Marks
number

2 a cross in box C (neutrons and protons) 1

b i 6 1

ii 14 1
1.Atomic Theory

Classified Chemistry
c cross in box B (the numbers of electrons and 1
protons are equal)

d M1 same number of protons Ignore references to electrons 1

/ (they both have) 6 protons
M2 different numbers of neutrons / more neutrons If number of extra neutrons specified, 1
it must be 2
Reject different numbers of electrons
Ignore references to atomic number
and mass number

2C - Edexcel
e cross in box B (2.4) 1

TOTAL 7
165

Dr.Ann Mahdy
 1.Atomic Theory 166

Question
Answer Notes Marks
number

3 a cross in box D (neutrons and 1

protons)

b electrons 1

protons AND electrons Accept in either order 1

electrons 1

c cross in box A (2.8) 1

d i same number of protons Reference to atoms or 1

elements not essential
different numbers of neutrons 1
Do not award M2 if incorrect
statement about electrons

Max 1 if reference to
molecules/compounds/ions

ii 20.2/Ar closer to 20 (than 22) OWTTE 1

e i unreactive OWTTE 1

Accept does not react

ii (atoms) do not (readily) Accept outer shell complete 1

lose/gain electrons

OR
Accept orbit
contain 8 electrons in outer
shell/energy level Ignore references to Group
number
Ignore stable

(Total for Question 1 = 10 marks)

Classified Chemistry 2C - Edexcel Dr.Ann Mahdy

 Question
Answer Notes Marks
number

4 a i C (neutrons and protons) 1

ii A (6) 1

iii D (11) 1
1.Atomic Theory

b 4 1

Classified Chemistry
c i P AND T 1

ii S 1

d (one) more electron than protons Accept more electrons than protons 1
Accept fewer protons than electrons
OR
Accept 2 electrons and 1 proton
(one) fewer proton than electrons
Ignore references to electron gained

2C - Edexcel
Total 7 marks
167

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
5 a
M1 protons and electrons correct 2

M2 neutrons correct
1.Atomic Theory

Classified Chemistry
b i 3 1

ii M1 33 Accept has 2 more protons (than X) 2

M2 Z is two places/columns/groups/positions after X Ignore references to atomic number

OR increasing by 2
Z is in Group 5 and X is in Group 3 Ignore number of protons increases with
group number
Ignore references to elements being
arranged according to number of protons

2C - Edexcel
31 + 5 – 3 = 33 scores 2 marks

iii 2.8 / 2,8 / 2 and 8 separated by other mark Do not accept 28 (ie no space) 1
eg : or / or ) or space Accept correct sp notation
168

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
5 b iv Accept rings and energy levels in place of 2
shells in M1 and M2
M1 (similarity)
1.Atomic Theory

one electron/same number of electrons in outer shell Accept valence electrons in place of
outer shell electrons

Classified Chemistry
Accept configuration ends in 1
Accept same outer shell
Accept 2 electrons in first/inner shell

M2 (difference) Accept going down the column there is 1

different number of (electron) shells more shell
/ T has (one) more (electron) shell Ignore T has an extra number
/ J has (one) less (electron) shell Ignore T has 8 more electrons
/J has 2 shells and T has 3
/J is 2.1 and T is 2.8.1

2C - Edexcel
Total 8 marks
169

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

6 c i 4 1
1.Atomic Theory

ii 21 1

Classified Chemistry
Question
Answer Notes Marks
number

7 a i Atomic Mass Number Number M1 for 19 protons in top row AND atomic
number number of of number of 19
protons neutrons
M2 for 20 neutrons in top row
3

2C - Edexcel
19 20
M3 for mass number of 41
19 41

ii M1 (6 × 0.074) + (7 × 0.926) ACCEPT (6 × 7.4) + (7 × 92.6)

100
2
M2 = 6.9 Answer must be to 1 dp
Correct final answer without working scores 2
marks
170

Dr.Ann Mahdy
 Question
Answer Accept Reject Marks
number
1 (a) (i) B 1
(ii) A 1
(iii) E 1
2.Periodic Table

(iv) C 1
(b) (i) Atomic number 1

Classified Chemistry
(ii) Electrons in the outer shell 1
Total 6

Question
Answer Notes Marks
number
2 (a) gallium / Ga 1

(b) sodium / magnesium / aluminium / Na / Mg / Al 1

2C - Edexcel
(c) fluorine / F / F2 1

(d) nitrogen / N / N2 1

(e) neon / argon / krypton / xenon / radon 1

/ Ne / Ar / Kr / Xe / Rn
Total 5
171

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

3 a i period Ignore number of period 1

ii Any two of Ignore symbols Na, Mg, Al 1

sodium / magnesium / aluminium
2.Periodic Table

Classified Chemistry
iii Ar / argon If name and symbol both given, then
2
both must be correct
(it does) not easily gain/lose electrons Accept (it has) a full outer shell
OR Ignore 2.8.8
has 8 electrons in outer shell Ignore inert/noble gas
Ignore references to Group number
Ignore stable
M2 DEP on M1

b one electron/same number of electrons Reject incorrect number of electrons 1

AND Ignore similar electronic configurations

2C - Edexcel
reference to outer/valence (shell/energy Ignore actual electronic configurations
level/orbit)

c i C / carbon 1

ii S / sulfur 1

d 8 for both protons AND electrons Accept words 1

10 neutrons Accept words 1

(Total for Question 3 = 9 marks)

172

Dr.Ann Mahdy
2.Periodic Table 173

Question
Answer Notes Marks
number
4 (a) Ignore name 1
and formula of
compound

(i) Na / sodium / Mg / magnesium

Accept
aluminium
If both name
and formula
(ii) Si / silicon / P / phosphorus / S / sulfur / given both
Cl / chlorine must be 1
correct

If both name
and formula
given both
must be
correct

Classified Chemistry 2C - Edexcel Dr.Ann Mahdy

 Question
Answer Accept Reject Marks
number
1 (a) (giant) ionic any other 1
answer
IGNORE three-dimensional / lattice
(b) M1 and M3 can be scored from labelled diagrams
3.BONDING

sodium:
M1 – positive ions/cations/Na+ and (delocalised/sea of) electrons Sodium / metal ions 1
atoms/molecu
IGNORE metal ions les

Classified Chemistry
M2 – (electrostatic) forces/attraction between positive nuclei
ions/cations/Na+ and 1
(delocalised) electrons intermolecular
IGNORE references to metallic bonding forces

sodium chloride: 1
+ — oppositely charged atoms/molecu
M3 – positive and negative ions/cations and anions / Na and Cl
(ions) ions les
nuclei 1

2C - Edexcel
M4 – electrostatic forces/attraction between (oppositely chlorine ions if stated intermolecular
charged/positive as being negative forces
and negative) ions / cations and anions / Na+ and Cl—
IGNORE references to ionic bonding reference to 1
covalent loses
M4
comparison:
M5 - forces in Na are weaker (than forces in NaCl) can be awarded less energy required
even if an to overcome forces in
incorrect description of the forces has been given. Na
bonds / lattice for
[standalone] forces
174

ORA

Dr.Ann Mahdy
 Question Mar
Answer Accept Reject
number ks
1 (e) M1 - 8 electrons around Na any combination of dots and 1
crosses
0 electrons
M2 - 8 electrons around Cl.
3.BONDING

IGNORE inner shells even if incorrect 1

IGNORE starting diagrams showing atoms
either with or without arrow to show movement

Classified Chemistry
of electron

M3 - correct charge on both Na and Cl 1

[standalone]

Question
Answer Accept Reject Marks
number

2C - Edexcel
2 (a) D (a molecule) 1

(b) A (covalent) 1

(c) NH3 H3N 1

Total 3 marks
175

Dr.Ann Mahdy
 Question
Answer Accept Reject Marks
number

3 (a) 3
Element Arrangement Arrangement Charge
of electrons in of electrons in on ion
3.BONDING

atom ion

2.8.8 (1)+/+1 K(1)+ / K+1

Classified Chemistry
2.8.8 2−/−2 S2− / S−2

M1 – both arrangements correct

M2 – charge on potassium ion positive for potassium

and negative for sulfide
M3 – charge on sulfide ion for 1 mark

(b) (i) ions move/travel (to the electrodes) ions are free to move / electrons free 1
ions are mobile to move

2C - Edexcel
M1 (electrostatic) forces (of attraction) between (oppositely
(ii) ionic bonding / ionic 3
charged) ions
bonds

M2 are (relatively) strong

M3 large amount of energy required to overcome the forces break the bonds
/ separate the ions from the lattice

M2 dep on mention of forces (of attraction) or bonds

Mention of covalent bonds or intermolecular forces no M1

176

Dr.Ann Mahdy
Total 7 marks
 Question
Answer Notes Marks
number

4 (a) does not easily lose / gain electrons Accept has a complete/full outer shell/octet (of
3.BONDING

electrons)
1
Accept has 8 electrons in outer shell
Ignore references to being stable / inert / a noble gas

Classified Chemistry
(b) B (2.8.18.8) 1

(c) (i) M1 for idea of electron transfer / loss and gain of 0/3 for electron sharing
electron(s) Ignore covalent

eg calcium loses, chlorine gains electrons

M2 for direction of transfer 3
eg calcium loses 2, (each) chlorine gains 1

2C - Edexcel
M3 for number of electrons transferred Penalise use of chloride in place of chlorine once only
All marks may be scored from a correctly labelled
diagram
+2
(ii) Ca2+ Accept Ca / Ca++
Reject all other ions
Penalise incorrect use of lower and upper case letters
and position of charge 1
If equation written containing calcium ion formula,
the ion must be identified in some way, such as
circling or underlining

(iii) A calcium (and) calcium 1

177

Dr.Ann Mahdy
3.BONDING 178

Question
Answer Notes Marks
number
5 (b) (i) Allow electrons 3
on brackets

Allow any
combination of
dots and
crosses
M1 correct electronic configuration for
magnesium ion and correct charge on
Allow 0 or 8
ion
electrons in
outer shell
M2 correct electronic configuration for
both chloride ions

M3 correct charges on both chloride ions

M3 indep
(ii) 2
M1 electrostatic attraction/forces
between ions

M2 of opposite charge

accept positive

Classified Chemistry 2C - Edexcel Dr.Ann Mahdy

3.BONDING 179

and negative
ions
accept cations
and anions
M2 dep on M1
Accept
attraction/forc
es between
(iii) oppositely 3
M1 attraction (between ions) is strong charged ions
for 1 mark
only
Reject
M2 lots of ions (in structure) / giant references to
structure / lattice / lots of/many bonds atoms/molecul
es/IMF for M1
M3 (therefore) lot of (thermal/heat) and M2
energy required to overcome
attraction / to break down the lattice
Accept strong
(ionic)
bonding/strong
( ionic) bonds

Accept lot of
(thermal/heat)
energy
required to
break (ionic)
bonds

If any
reference to
attraction
between
atoms/molecul
es/electrons
scores 0/3
If any
reference to
covalent
bonding/covale
nt
structure/IMF
scores 0/3

Classified Chemistry 2C - Edexcel Dr.Ann Mahdy

 Question
Answer Notes Marks
number
3.BONDING

6 (a) 1 mark for each correct 2

ion
IGNORE charges on ion

Classified Chemistry
ALLOW any combination
of dots and crosses
Diagram showing sharing
of electrons scores 0
(b)
M1 all four bonding pairs 2
correct, and only 8
electrons shown in
outer shell of carbon

2C - Edexcel
M2 all non-bonding pairs
correct

IGNORE inner shells even

if incorrect

If rings are drawn then

both bonding electrons
must be in the
overlapping area

M2 DEP on M1
180

Dr.Ann Mahdy
 3.BONDING 181

Question
Answer Notes Marks
number
(c) M1 (high melting point of LiF) 4
strong forces (of attraction) ACCEPT strong (ionic)
between (oppositely charged) ions bonding / strong (ionic)
/ strong forces (of attraction) bonds
between Li+ and F− ACCEPT large amount of
energy required to overcome
the forces between the
ions/break (ionic) bonds
REJECT any reference to
molecules or intermolecular
forces
REJECT reference to atoms

M2 (good conductivity of LiF) ACCEPT ions can move

ions are mobile REJECT any reference to
electrons are
mobile/delocalised electrons

ACCEPT weak van der

M3 (low melting point of CF4) Waals forces / weak London
weak forces (of attraction) forces / weak dispersion
between molecules / weak forces
intermolecular forces (of attraction) ACCEPT very little energy
required to overcome the
intermolecular forces.
ALLOW weak intermolecular
bonds
REJECT any references to
covalent bonds broken

M4 (poor conductivity of CF4) IGNORE no free

molecules are not charged / electrons/all electrons used
molecules are neutral / no charged in bonding
particles IGNORE there are no ions
ALLOW no delocalised /
no mobile electrons
Total 8

Classified Chemistry 2C - Edexcel Dr.Ann Mahdy

 Question
Expected answer Accept Reject Marks
number
1 (a) Giant (structure / lattice / atomic / molecular) Macromolecular Max 2 for mentioning 1
of ionic or metallic
Covalent bonding or 1
Intermolecular forces
Idea that (covalent) bonds are broken 1
Bonds loosened
(Covalent bonds) are strong / many bonds (are 1

Classified Chemistry
4.SOLID STRUCTURE

broken) / lots of {energy/heat} required

NB No penalty for referring to graphite

(b) Layers slide / slip / move over each other Sheets / planes slide Rows slide 1
IGNORE particles in layers such as atoms, but
REJECT if ions / molecules / electrons for first 1
mark only
Any indication that the Any reference to
Weak (intermolecular forces of) attraction between forces are those of bonds between layers

2C - Edexcel
layers / weak van der Waals (forces of attraction) attraction, e.g. forces / molecules
between layers overcome / forces are
broken / forces hold
the layers together

IGNORE references to bonds within the layers

(c) Delocalised electrons Refs to atoms / ions / 1

molecules scores 0/2
(which) move / mobile / flow 1
IGNORE references to “carrying” charge / current
182

Dr.Ann Mahdy
 1 (d) Any two from:

Not a giant structure Smaller molecules / MAX 1 for any 2

IGNORE simple molecular simpler structure than mention of covalent
diamond bonds are broken in
Buckminster
Weak intermolecular (forces of ) attraction / fullerene
weak (forces of) attraction between molecules / Any indication that the
weak van der Waals (forces of attraction) forces are those of Any reference to

Classified Chemistry
4.SOLID STRUCTURE

between molecules attraction, e.g. forces bonds between

overcome / forces broken / molecules
forces hold the molecules
together
No covalent bonds break (when melting)

First and third marking

points can be awarded for
correct comparisons
between the two

2C - Edexcel
structures, e.g.
buckminsterfullerene is
simple molecular whereas
diamond is giant covalent
scores the first mark;
weak intermolecular forces
of attraction in
buckminsterfullerene are
broken as opposed to the
covalent bonds in diamond
(scores the 3rd mark, as
well as the 2nd)
183

Dr.Ann Mahdy
Total 10 Marks
 Question
Answer Notes Marks
number
2 b i diagram showing: 3
M1 minimum of 5 circles in regular pattern in 2 rows

M2 +/2+ charges in each circle / appropriate key Accept labelled as cations/positive ions
not just ions

Classified Chemistry
4.SOLID STRUCTURE

Reject atoms / protons / nuclei

eg e / e– / – / (shaded) area labelled electrons

M3 some indication of electrons between ions Do not award M3 if electrons shown in circles
/ appropriate key more than half the size of the ions
Ignore lines between circles
Max 1 if negative ions shown
Reject electrons shown in pairs between nickel
particles for M3
Ignore intermolecular forces label

2C - Edexcel
Example:

Dr.Ann Mahdy
184
 Question
Answer Notes Marks
number
2 b ii malleability (2 marks): 4

M1 layers / sheets / planes / rows

AND
(positive) ions / atoms / particles Reject molecules / protons / electrons

Classified Chemistry
4.SOLID STRUCTURE

M2 slide (over each other) M2 needs reference to either layers or

equivalent OR ions/particles/atoms
Allow OWTTE, eg slip / flow / shift / roll / move
M2 DEP on mention of EITHER layers or
equivalent
OR mention of ions or equivalent

Do not award M2 if protons / electrons / nuclei /

molecules in place of ions, etc

2C - Edexcel
If reference to ionic bonding / covalent bonding
/ molecules / intermolecular forces, no M1 or
M2
conductivity (2 marks):

M3 – delocalised electrons Accept sea of electrons

Ignore free electrons

M4 – that flow (when a potential difference is applied) Accept move / mobile in place of flow
M4 DEP on mention of electrons
Ignore reference to intermolecular forces for M3
and M4

Total 10 marks

Dr.Ann Mahdy
185
 Question
Answer Notes Marks
number

3 (a) M1 for front face all correct

M2 for rear face all correct

M2 DEP on M1 2

Classified Chemistry
4.SOLID STRUCTURE

Do not penalise X in place of +

Ignore symbols such as K and Cl
Do not penalise use of Na+ in place of K+

2C - Edexcel
186

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
1 c i M1 for all formulae correct
M2 for balancing AND reversible arrow 2
5.EQUATION

Ignore state symbols

CO + H2O ⇌ CO2 + H2

M2 DEP on M1

Classified Chemistry
ii (carbon/it) gains/reacts with oxygen / Accept oxygen atom/molecule 1
oxygen is added Accept increase in oxidation number
Accept actual oxidation numbers if correct (+2 to
+4)
Reject oxide ion
Ignore references to gain or loss of electrons

iii M1 for all formulae correct and on the correct sides

K2CO3 + CO2 + H2O → 2KHCO3 M2 for balancing 2
M2 DEP on M1

2C - Edexcel
(Total for Question 8 = 9 marks)

Dr.Ann Mahdy
187
 Question
Answer Notes Marks
number

2 (a) Substance Element or Type of Ignore qualifiers for covalent, eg

5.EQUATION

compound bonding polar / dative

ammonia compound covalent

Classified Chemistry
hydrogen (compound) covalent All 6 correct = 3 marks
chloride 3
5 or 4 correct = 2 marks
oxygen element (covalent)
3 or 2 correct = 1 mark
magnesium compound ionic
oxide 1 or 0 correct = 0 marks

2C - Edexcel
(b) B (MgO) 1

(c) B (g) 1

Total for Question 2 5

188

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
1 c (i) M1 bromine / Br / Br2 Reject bromide / Br − 1

(ii) M1 reduction and oxidation (at the same time) Accept oxidisation 1
6.REDOX

Ignore oxygenation

Accept loss and gain of electron(s)

Reject loss of electrons by chlorine

Classified Chemistry
(molecules) / gain of electrons by
bromide (ions)

Reject reduction is loss of electrons /

oxidation is gain of electrons

Ignore references to other reaction

types, eg displacement / reversible

Ignore references to atoms / ions /

2C - Edexcel
molecules / elements

Question
Answer Notes Marks
number

2 a i tungsten(VI) oxide / tungsten trioxide Accept tungsten oxide 1

Reject tungsten oxide with other
oxidation numbers or prefixes such as
mono- and di-

ii (1) 3 (1) 3 Accept multiples and fractions 1

iii loss of oxygen (by it / tungsten / tungsten oxide) Accept decrease in oxidation number of 1
189

Dr.Ann Mahdy
tungsten
Accept tungsten ions gain electrons
 Question
Answer Notes Marks
number
3 c Zn / zinc (atom) 1
(it) loses (2) electrons / gives electron(s) to Accept Fe3+ gains electron(s)/is 1
6.REDOX

Fe3+ reduced/oxidation number decreases

/zinc is oxidised / zinc increases its oxidation Ignore Fe3+ converted to Fe2+
number / Zn converted to Zn2+
Reject iron/Fe gains electrons

Classified Chemistry
M2 DEP on M1

Question
Answer Notes Marks
number

4 c iv M1 (correct products) KCl AND I2 Accept in either order

M2 2 2 M2 DEP on M1

c v (both) reduction AND oxidation occur (in the same Accept (both) gain AND loss of 1

2C - Edexcel
reaction) electrons occurs (in the same
reaction)

Accept (both) gain AND loss of

oxygen occurs (in the same reaction)

Accept (both) increase AND decrease

of oxidation states/oxidation
numbers (in the same reaction)

Ignore incorrect species being

oxidised and reduced / losing and
190

gaining electrons

Dr.Ann Mahdy
 vi M1 (species) I— / iodide (ion) 1

M2 (reason) loss of electron(s) Accept increase in oxidation number 1

6.REDOX

OR oxidation number changes from

−1 to 0

Ignore number of electrons lost

Classified Chemistry
M2 DEP on M1 correct, or near miss
e.g. iodine

Total 10 marks

2C - Edexcel
191

Dr.Ann Mahdy
 6.REDOX 192

Question
Answer Notes Marks
number

5 (b) (i) 2Al + Fe2O3 → Al2O3 + 2Fe ACCEPT multiples 1

and halves

(ii) M1 aluminium 2

M2 because it has gained oxygen

OR

because it has lost electrons

OR

because its oxidation number has

increased

OR

because its oxidation number has

changed from 0 to +3
M2 DEP on M1

(iii) M1 (powders have) larger surface area 2

M2 (therefore) faster reaction

ACCEPT reverse
arguments
IGNORE references
to collisions between
particles

Classified Chemistry 2C - Edexcel Dr.Ann Mahdy

7.ELECTROLYTES AND EXTRACTION OF METALS 193

Question Answer Mark

Number
1(a)(i) (on diagram) – in left and + in right 1

Question Answer Mark

Number
1(a)(ii) H+
Gains electrons
(reject OH- =0/2) 2

Question Answer Mark

Number
1(a)(iii) (on diagram) horizontal line in right-hand tube about
halfway between hydrogen gas level and top of tube
(explanation)(1)
for same number of electrons in (i) and (ii)
2 moles / molecules of hydrogen formed for 1 mole /
molecule of oxygen (2)
3

Classified Chemistry 2C - Edexcel Dr.Ann Mahdy

 Question
Expected answer Accept Reject Marks
number
2 (a)(i) Magnesium Mg 1

(a)(ii) It would react with the sulfuric acid / the clouds It is too reactive / very “reactive” by itself 1
/ the atmosphere / it will fizz reactive / the most
reactive

Dissolve in the

Classified Chemistry
(sulfuric) acid/ eq

(b) it has low melting point / would melt / Lead would be a liquid 1
temperature on Venus is higher than the Answer using data from
melting point of lead (ora) table e.g. 328°C is
IGNORE heavy / dense lower than temp on
Venus

(c) Titanium Ti 1

2C - Edexcel
Any two from: 1
• it has a low density / is lightweight The probe would be Light on its own /
light light in weight on its 1
7.ELECTROLYTES AND EXTRACTION OF METALS

• it has a high melting point / wouldn’t melt own

/ temperature on Venus is lower than the Remains solid
melting point of titanium (ora)
• does not react with sulfuric acid / the
clouds / the atmosphere / it will not fizz

Reason marks can be

scored for copper
(density mark would
need to be compared
to lead)
194

Dr.Ann Mahdy
Total 6 Marks
 Question
Answer Notes Marks
number
3 c M1 slag Accept calcium silicate 1
Ignore formula

d (i) M1 aluminium/it is more reactive than iron/carbon Comparison with iron or carbon must 1
OR be stated or implied, eg not just
above iron/carbon in reactivity series aluminium is (very/too) reactive
OR

Classified Chemistry
cannot be reduced by/does not react with carbon Accept reverse argument for iron
(monoxide)
OR
cannot be displaced by carbon

(ii) M1 (cost of) electricity Accept keeping electrolyte molten 1

Accept high current
Ignore energy
Ignore references to electrode
replacement

2C - Edexcel
3 e M1 electrode(s) / to conduct electricity Accept cathode / anode 1
7.ELECTROLYTES AND EXTRACTION OF METALS

f M1 Al3+ + 3e → Al M1 for both aluminium formulae on

M2 2O2– → O2 + 4e / 2O2– – 4e → O2 correct sides of equation 3
M3 M2 for both oxygen formulae on
correct sides of equation
M3 for balancing both equations even
if one or both reversed
Accept in either order
195

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

4 a (i) M1 arrow pointing towards negative electrode Accept by X / on wire / by power 1

supply (as long as pointing in correct
direction

(ii) M1 hydrogen / H2 Ignore H 1

Classified Chemistry
(iii) M1 4OH– → 2H2O + (1)O2 + 4e– Accept fractions and multiples 1
Accept e in place of e–
Accept equation with – 4e– on LHS

Question
Answer Notes Marks
number
5 (a) A description linking five of the following points:
x set up tubes containing iron (nail) in rainwater and iron (nail)
in seawater

2C - Edexcel
x control tube / tube with iron (nail) and no water
x same mass of iron (nail) / same volume of water
x leave tubes for same length of time / stated time interval
7.ELECTROLYTES AND EXTRACTION OF METALS

x method to measure rusting e.g. colour change / mass change

x repeat experiment / more than one set of tubes set up max 5

(b) involves gain / addition of oxygen ACCEPT involves loss of electrons /

increase in oxidation number 1

Total: 6
196

Dr.Ann Mahdy
 Question
Q
Answer Acc
cept Reject Marks
number
6 (a) Solution Negativee Positive Substance
e
electrode
e electrodee left
1
silver sulfate
e silver correct forrmulae
potassium oxygen potassium throughout O for oxygen 2
nitrate nitrate

(b) (i) platinum carbon / graphite 1

Classified Chemistry
copper/ sillver / gold
/ titanium

(ii) c
to increase itts (electrical) conductivity / to make it a to increasee the 1
(better) (elecctrical) conduc ctor / to lower its (electrical)) concentrattion/numb
resistance er of ions
IGNORE references to carrying current / charge / adds s
hydrogen ion ns

2C - Edexcel
(c) (i) Moles/amoun
nt of hydrogen
n (produced) = 2 x number off molecules explanations
e
moles/amoun
nt of oxygen (produced) of hydrogeen b
based on atomms 1
(produced) is twice
7.ELECTROLYTES AND EXTRACTION OF METALS

ygen
that of oxy
IGNORE explanations base
ed on forming water

(ii)
olves in water//acid
(some of the) oxygen disso t
(some of the) oxygen reacts
o
oxygen rea acts with w
with
the (carbon) w
water/(sulfuric ) 1
electrode/tto form a
acid
CO2 (whichh then
dissolves)
197

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
7 (a) ethanol/it is more volatile/evaporates more Accept has a lower boiling point (than water) 1
quickly/more easily/evaporates in a shorter time Ignore reference to melting point(s)
Accept reverse arguments for water

Classified Chemistry
(b) i 0.3(0) (g) 1

ii some copper did not stick to (negative) Accept some copper dropped off
electrode/cathode
some copper removed during washing/drying 2
positive electrode/anode impure
OR
formed (anode) sludge
Any two for 1 each

2C - Edexcel
7.ELECTROLYTES AND EXTRACTION OF METALS
198

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
7 (c) i all 9 points plotted correctly to nearest gridline Deduct 1 mark for each error
Award these marks if points too faint to be seen
under correct line
Ignore point at 0.55

Must be drawn with a ruler

straight line of best fit Must go through origin

Classified Chemistry
Ignore extrapolation beyond (16,0.5)

ii point at (7.40, 0.20) circled

iii no charge/current/electricity passed OWTTE, eg

AND charge = 0, so mass (increase) = 0
no copper deposited/no change in mass/no Ignore references to direct proportion
electrolysis

iv line is straight / fixed gradient Ignore re-statements of the information given in the

2C - Edexcel
AND question, eg the greater the charge, the greater the
goes through origin mass (increase)
7.ELECTROLYTES AND EXTRACTION OF METALS

Question
Expected Answer Accept Reject Marks
number

8 (c) M1- oxygen air 2

IGNORE O O2
199

Dr.Ann Mahdy
M2 – water moisture/H2O
 Question
Answer Notes Marks
number

9 a too reactive / very reactive Accept words with equivalent meaning 1

OR eg highly

high in the reactivity series

Classified Chemistry
b i B (stage 2) 1

ii calcium chloride / CaCl2 If both name and formula given, mark 1

name only

iii (they / the ions) are mobile Accept free to move 1

Accept move to electrodes (allow even if
incorrect electrodes)

2C - Edexcel
Accept ions break free from lattice/crystal
Not just free
Allow they/ions are delocalised
7.ELECTROLYTES AND EXTRACTION OF METALS

Ignore references to conduction

— (—)
iv 2Cl → Cl2 + 2e Accept 2Cl— — 2e(—) → Cl2 1
200

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

9 d M1 Mix magnesium oxide and sulfuric acid (and heat)

M2 Use excess MgO

M3 Filter (before heating to remove some water)

Classified Chemistry
M4 Heat (the solution) to remove some water / for a If heated to dryness, no M4 or M5
short period of time 5

Allow place in a warm oven (to

M5 Leave to crystallise
evaporate the excess water) to form
crystals

2C - Edexcel
7.ELECTROLYTES AND EXTRACTION OF METALS
201

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
10 a i correct statement about connection between eg same number of electrons give same numbers of 1
number of electrons moles
and moles/molecules/amounts (of both gases)
OR

Classified Chemistry
reference to number of moles/molecules being eg equal moles of gases have equal volumes
equal (in both equations) / volumes are proportional to numbers of moles

ii (some/chlorine/it) is soluble / dissolves (in water Accept (some) oxygen also collected 1
/ in the solution) Reject chlorine reacts with graphite
OR Ignore chlorine gas escapes
(some/chlorine/it) reacts with water Reject reacts with sodium chloride
/ reacts with sodium hydroxide

iii Mark M1 and M2 independently 2

M1 (solution) alkaline / pH greater than 7 Ignore basic

2C - Edexcel
Accept any value above 7 up to 14
7.ELECTROLYTES AND EXTRACTION OF METALS

M2 (because) hydroxide ions / OH– (formed) Accept sodium hydroxide formed

Dr.Ann Mahdy
202
 Question
Answer Notes Marks
number

11 (b) (ii) 2H2O + 2e– → H2 + 2OH- M1 for H2O on lhs AND H2 and OH- on rhs and no
OR other formulae
2H+ + 2e– → H2
M1 for H+ on lhs AND H2 on rhs and no other
formulae

Classified Chemistry
M2 for e(–) and balancing of correct equation
2
Accept
M1 H + + e– → H
M2 2H → H2
M2 DEP on M1
Ignore state symbols

2C - Edexcel
(iii) M1 alkaline / alkali formed Accept pH above 7
7.ELECTROLYTES AND EXTRACTION OF METALS

M2 OH– Ignore names 2

Mark independently

Dr.Ann Mahdy
203
7.ELECTROLYTES AND EXTRACTION OF METALS 204

Question
Answer Notes Marks
number
12 (a) M1 iron reacted with oxygen Accept iron 2
combined/bonded
with oxygen
Accept iron oxide
formed
Accept iron is
oxidised
Ignore iron uses
oxygen
Ignore iron rusts
Ignore references
to reacting with
water

M2 all oxygen is reacted / (all) Accept references

oxygen used up / no oxygen left to 20% or 20cm3
of the air which is
oxygen used
up/reacted

Reject all iron

used up
Ignore reaction
has finished

(b) M1 iron(II) sulfate / iron sulfate reject any other 2

oxidation state

M2 hydrogen

Classified Chemistry 2C - Edexcel Dr.Ann Mahdy

 Question
Answer Notes Marks
number
13 a M1 oxygen / air ACCEPT O2 but not O
2
M2 water (vapour) / moisture ACCEPT H2O
IGNORE steam

b (hydrated) iron(III) oxide ACCEPT iron oxide / ferric oxide

REJECT ferrous oxide and iron with other

Classified Chemistry
oxidation numbers
IGNORE iron trioxide
1
ACCEPT Fe2O3(.xH2O)
IGNORE all other formulae

If both name and formula given mark name only

c M1 (galvanising) bucket / car body /

2C - Edexcel
railway bridge
7.ELECTROLYTES AND EXTRACTION OF METALS

M2 (oiling) bicycle chain / car 3

engine
M3 (painting) car body / railway DO NOT AWARD M3 for car body/railway
bridge bridge if already scored for M1

d M1 zinc corrodes/oxidises/reacts in preference to REJECT zinc rusts

iron IGNORE reference to sacrificial protection
ACCEPT for M1 zinc atoms react with iron(II)
ions
2
M2 (because) zinc is more reactive than iron / ACCEPT for M2 iron(II) ions are converted to
zinc (atoms) lose electrons more readily (than iron atoms
205

Dr.Ann Mahdy
do iron atoms)
 Question
Answer Notes Marks
number

14 a
M1 both bungs inserted AND electrodes connected to
battery

M2 both tubes inverted over electrodes

Classified Chemistry
M3 solution placed in the voltameter and labelled as 3
potassium chloride / KCl(aq)

For M3, ignore all three liquid levels, except that the level in
the voltameter must be above the bottoms of both tubes if
present

2C - Edexcel
Polarity Equation M1 for 2Cl‒ → Cl2 + 2e(‒)
ACCEPT 2Cl‒ ‒ 2e(‒) → Cl2
– –
–(ve) (2H2O + 2e → H2 + 2OH )
7.ELECTROLYTES AND EXTRACTION OF METALS

2
M2 for –(ve) in top row AND +(ve) in bottom row
+(ve) 2Cl– → Cl2 + 2e(‒) ACCEPT negative and positive
IGNORE cathode and anode

c burns with a pop / squeak Must be reference to test and result

Reference to spill/match with no indication of flame is not
OR enough
ACCEPT splint for spill 1
use burning/lit spill / use flame to see if
REJECT reference to glowing spill/splint
pop/squeak
Ignore flame extinguished
'Squeaky pop test' alone is not sufficient
206

Dr.Ann Mahdy
8.ACID , BASES AND SALT PREPARATION 207

Question Answer Mark

Number
1(c)(i) Yellow / orange - not red 1

Question Answer Mark

Number
1(c)(ii) Carbonic (acid)
H2CO3 2

Question Answer Mark

Number
1(d) Ionic
covalent 2

Question Answer Mark

Number
2(c) x Pipette / burette to measure sulfuric acid
x Sodium hydroxide in burette
x Indicator used and colour change (NOT universal
indicator)
x Add sodium hydroxide gradually near end point
(and swirl) 4

Classified Chemistry 2C - Edexcel Dr.Ann Mahdy

 Question
Answer Accept Reject Marks
number
3 (a) (i) any named soluble metal sulfate / ammonium correct formula concentrated sulfuric 1
sulfate / (dilute) sulfuric acid acid
2⎯
(ii) correct formulae for all compounds Pb2+ + SO4  1
(mark consequentially on the sulfate given in PbSO4

Classified Chemistry
(a)(i), even if insoluble, except lead(II) sulfate) for 2 marks
1
balanced

(iii) filter 1

wash / rinse (with distilled / deionised water) 1

If no reference to what is being washed, assume
that the residue is being washed 1
8.ACID , BASES AND SALT PREPARATION

2C - Edexcel
filter paper / kitchen roll / blotting paper /
absorbent paper /leave (to dry) / (pace in)
desiccator / (place in warm) oven / heat

If no filtration MAX 1.
If implication that filtrate is washed or evaporated
, neither M2 nor M3 can be awarded
Do not penalise careless use of solution or liquid
for reaction mixture
208

Dr.Ann Mahdy
 Question
Expected Answer Accept Reject Marks
number
3 (b) Any two from

bubbles (of gas) / fizzing / effervescence gas given off

Ignore carbon dioxide

solid / lead(II) carbonate disappears dissolves / less solid

Classified Chemistry
solution formed / colourless liquid any specific colour 2
Ignore incorrect starting colours

Ignore heat produced and temperature change

Total 8
8.ACID , BASES AND SALT PREPARATION

2C - Edexcel
209

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

4 a (i) M1 more accurate Accept more precise / gives an exact 1

value

(ii) M1 (thermal) insulator /poor conductor/keeps heat in/ Accepts traps heat 1
reduces heat loss

Classified Chemistry
(iii) M1 stirring/mixing/swirling Ignore name of apparatus used 1

(iv) M1 temperature goes down/stops rising/stays constant Accept measure pH/when pH = 1

7/when pH is less than 7
Reject changing to any pH value > 7
Accept use of any indicator (named
example or just indicator)
Ignore colour changes

b M1 19.4 1
8.ACID , BASES AND SALT PREPARATION

2C - Edexcel
M2 23.1 1
M3 3.7 CQ on temperatures recorded 1
Penalise negative sign
Penalise second decimal place
values, except zeroes, for M1 and M2
M1 and M2 both correct but wrong
way around scores 1
210

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
4 c (i) M1 9 points plotted correctly to nearest gridline Deduct 1 for each error 2
M2 If points not visible beneath line,
assume them to be on line
M3 straight line of best fit through first 5 points 1
M4 straight line of best fit through last 4 points 1
If lines do not cross or are joined by
curve or straight line, only M3 or M4

Classified Chemistry
can be awarded

(ii) M1 volume of acid CQ on where lines cross Accept answer ± 0.5 to minimum of 1
1 dp
M2 maximum temperature CQ on where lines cross Accept answer ± 0.1 to minimum of 1
1 dp
Do not award either mark if lines do
not intersect
Apply dp penalty once only
Award 1 mark if both values correct
8.ACID , BASES AND SALT PREPARATION

2C - Edexcel
but recorded in wrong places

d M1 55 (× 4.2 × 5.5) 1
M2 1270.5 Accept any value between 1270 and 1
1271
Accept 1300
M2 CQ on M1
If vol used is 25, answer is 577.5
Accept any value between 577 and
578 accept 580
If vol used is 30, answer is 693
Accept 690
Ignore signs
Correct final answer without working
211

Dr.Ann Mahdy
scores 2 marks
 Question
Answer Notes Marks
number

5 a (i) M1 more accurate Accept more precise / gives an exact 1

value

(ii) M1 (thermal) insulator /poor conductor/keeps heat in/ Accepts traps heat 1
reduces heat loss

Classified Chemistry
(iii) M1 stirring/mixing/swirling Ignore name of apparatus used 1

(iv) M1 temperature goes down/stops rising/stays constant Accept measure pH/when pH = 1

7/when pH is less than 7
Reject changing to any pH value > 7
Accept use of any indicator (named
example or just indicator)
Ignore colour changes

b M1 19.4 1
8.ACID , BASES AND SALT PREPARATION

2C - Edexcel
M2 23.1 1
M3 3.7 CQ on temperatures recorded 1
Penalise negative sign
Penalise second decimal place
values, except zeroes, for M1 and M2
M1 and M2 both correct but wrong
way around scores 1
212

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
5 c (i) M1 9 points plotted correctly to nearest gridline Deduct 1 for each error 2
M2 If points not visible beneath line,
assume them to be on line
M3 straight line of best fit through first 5 points 1
M4 straight line of best fit through last 4 points 1
If lines do not cross or are joined by
curve or straight line, only M3 or M4

Classified Chemistry
can be awarded

(ii) M1 volume of acid CQ on where lines cross Accept answer ± 0.5 to minimum of 1
1 dp
M2 maximum temperature CQ on where lines cross Accept answer ± 0.1 to minimum of 1
1 dp
Do not award either mark if lines do
not intersect
Apply dp penalty once only
Award 1 mark if both values correct
8.ACID , BASES AND SALT PREPARATION

2C - Edexcel
but recorded in wrong places

d M1 55 (× 4.2 × 5.5) 1
M2 1270.5 Accept any value between 1270 and 1
1271
Accept 1300
M2 CQ on M1
If vol used is 25, answer is 577.5
Accept any value between 577 and
578 accept 580
If vol used is 30, answer is 693
Accept 690
Ignore signs
Correct final answer without working
213

Dr.Ann Mahdy
scores 2 marks
 Question
Answer Notes Marks
number

5 e (i) M1 1.5 × 0.025 1

M2 0.0375 Correct final answer scores 2 marks 1
37.5 scores M2 only

(ii) M1 1800 ÷ 0.0375 /1800 ÷ answer to (e)(i) Accept correct use of 1.8 in place of 1
1800

Classified Chemistry
M2 48 (kJ/mol) M2 CQ on M1 provided 1800 or 1.8 1
used correctly
If 37.5 in (a)(i) then answer is 0.048
(kJ/mol)
Correct final answer scores 2 marks
Ignore answer in J/mol
Ignore signs

Total 19 marks
8.ACID , BASES AND SALT PREPARATION

2C - Edexcel
214

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
6 (a) (i) neutralisation ACCEPT exothermic 1

(ii) KOH + HCl ĺ KCl + H2O 1

(iii) orange ACCEPT red 1

(iv) 28.75

Classified Chemistry
2.20 NOT 2.2
26.55 3rd mark consequential on other two 3

(b) (i) ticks under 26.70 and 26.50 1

(ii) 26.70 + 26.50 consequential on ticked results

2
8.ACID , BASES AND SALT PREPARATION

= 26.6(0) 2nd mark consequential on 1st 2

2C - Edexcel
215

Dr.Ann Mahdy
 (c) Any two from the following: In each case, 1 mark for identifying
P: initial solution contaminated with indicator the problem; and 1 mark for a
I: repeat titration / mix same volumes with no indicator / add correct suggestion for that problem
charcoal and filter (to remove indicator)

P: solution heated for too little / too long a time

I: evaporate until crystallisation point / check solution with glass rod

P: liquid poured off when crystals start to form

I: leave to cool until crystallisation complete

Classified Chemistry
P: crystals lost when solution poured off
I: filter / centrifuge / decant carefully to obtain crystals

P: blotting paper may not dry crystals completely

I: place crystals in (warm) oven to dry max 4

Question
8.ACID , BASES AND SALT PREPARATION

Expected Answer Accept Reject Marks

2C - Edexcel
number
7 pH at pH at Correct
start end letter
7 7 A 1
7 11 E 1
14 7 C 1
7 6 B 1

Total 4
216

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

8 c i hydrogen / H2 Ignore H 1

Classified Chemistry
ii becomes smaller / disappears Accept dissolves 1
Ignore references to bubbles

iii acidic / contains (hydrochloric) acid / hydrogen ions Accept pH below 7 or any value below 1
/ H+ (ions) 7

iv not acidic / no (hydrochloric) acid (formed) / no Reject references to alkali(ne) or pH 1

hydrogen ions / no H+ (ions) above 7
OR Ignore neutral
8.ACID , BASES AND SALT PREPARATION

HCl/hydrogen chloride does not ionise / dissociate Do not accept it/hydrochloric acid in

2C - Edexcel
place of HCl
217

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

9 a M1 concentration Ignore from the same bottle 1

M2 temperature / same temperature as acid 1
Accept in either order
Ignore references to volume

Classified Chemistry
b M1 19.4 Award 1 for both temperatures 1
M2 16.9 correct but in wrong order 1
M3 (+)2.5 CQ on temperatures recorded 1
Penalise negative sign

c i cross in box D (The volume of acid used was 1

50.0 cm3 instead of 25.0 cm3)

ii cross in box D (The alkali was added in 10.0 cm3 1

8.ACID , BASES AND SALT PREPARATION

portions but were recorded as

2C - Edexcel
5.0 cm3 portions)

d M1 Deduct 1 for each error

M2 all points plotted correctly to nearest gridline If points not visible beneath line, 2
assume them to be on the line
M3 straight line of best fit through first 4 points Lines must be drawn with a ruler 1
M4 straight line of best fit through last 3 points Penalise freehand once only 1
ECF on incorrectly plotted points
218

Dr.Ann Mahdy
 If first line drawn to (23.6,20.0), do
not award M3
If lines do not cross or are joined by
curve or straight line, only one of M3
and M4 can be awarded

Classified Chemistry
8.ACID , BASES AND SALT PREPARATION

2C - Edexcel
Question
Answer Notes Marks
number

9 e M1 volume of alkali CQ on where lines cross Accept answer to nearest gridline to 1

min 1 dp
M2 maximum temperature CQ on where lines cross Accept answer to nearest gridline to 1
min 1 dp
Penalise missing dp once only
If both values correct but in wrong
order, award 1/2
0/2 if lines do not cross
219

Dr.Ann Mahdy
 Question
Answer Notes Marks
number
10 a decomposition / breakdown / breakup / Ignore specific examples that do not
splitting / chemical change include key words (eg obtaining
aluminium from its ore)
Ignore separation / movement of ions
2
by electricity / (electric) current
/ (flow of) electrons

Mark independently

Classified Chemistry
b A = chlorine / Cl2 Ignore Cl
B = hydrogen / H2 Ignore H
C = sodium hydroxide / NaOH Ignore references to sodium chloride
If both name and formula given, both 3
must be correct, but ignore Cl and H
Award 1 mark for chlorine and hydrogen
the wrong way round
8.ACID , BASES AND SALT PREPARATION

Question

2C - Edexcel
Answer Notes Marks
number
10 c i so that ions are mobile/can flow/free to move Accept Na+ / Cl– in place of ions
(in liquid) Ignore references to charged species and
OR particles
ions not mobile / cannot flow/ not free to Reject references to moving electrons 1
move in solid Reject no ions in solid
Reference to solid can be implied (eg if not
molten…)

ii 2Cl– → Cl2 + 2e(–) M1 for Cl– on left and Cl2 on right

2
M2 for balancing, DEP on M1 correct
Accept – 2e(–) on LHS
If neither M1 nor M2 awarded, then award
220

1 mark for Cl– → Cl + e(–)

Dr.Ann Mahdy
or 2Cl– → 2Cl + 2e(–)
 8.ACID , BASES AND SALT PREPARATION 221

Question
Answer Notes Marks
number

11 a i no more precipitate forms Accept usual 1

alternatives for
OR
precipitate
no more lead(II) sulfate forms
Ignore references to
fizzing / temperature/
change in colour
ii cross in box D (sulfuric acid) 1

iii they would obtain sodium nitrate Accept the soluble salt 1
instead in place of sodium
OR nitrate
the filtrate does not contain lead(II)
sulfate/the insoluble salt
OR
the lead(II) sulfate/insoluble salt has
already been obtained in step 3
OR
they should have used the residue
(not the filtrate)
iv wash/pour water over the 1
solid/residue

warm / heat / place in oven / leave Accept on filter 1

(to dry) paper/kitchen
towel/tissue
paper/desiccator
v cross in box C (is insoluble in water) 1

b i 0.15(0) mol for BOTH substances 1

ii 0.15(0) ÷ 0.5(00) 1

0.3(00) dm3 / 300 cm3 Unit needed for mark 1

Correct final answer
with no working scores
2

(Total for Question 5 = 9 marks)

Classified Chemistry 2C - Edexcel Dr.Ann Mahdy

 Question
Answer Notes Marks
number

12 (a) M1 23.60 Award 1 mark for both M1 and M2 correct but in wrong order
Penalise missing zero in 2nd dp once only
M2 2.25 3

M3 21.35 CQ on M1 and M2

Classified Chemistry
(b) (i) ticks in columns 3 and 4 1

(ii) M1 23.50 + 23.70 If no results ticked in (i), then only use of concordant titres can score in
2 (ii)
If only one result ticked, then no marks can be scored in (ii)
Otherwise, both marks CQ on ticked results
2
M2 23.6(0) (cm3)
8.ACID , BASES AND SALT PREPARATION

Answers with zero as 2nd dp do not need trailing zero

2C - Edexcel
Answers obtained by averaging other titre values do require 2nd dp
Correct final answer with no working scores (2)

Question
Answer Notes Marks
number

12 (d) (i) white precipitate Ignore names and formulae

Apply list principle for incorrect observations such as 1
bubbles

(ii) barium sulfate Accept BaSO4

1
If both name and formula given, mark name only
222

Dr.Ann Mahdy
8.ACID , BASES AND SALT PREPARATION 223

Question
Answer Notes Marks
number
13 (a) Ignore state 1
CuO + 2HNO3 → Cu(NO3)2 + H2O symbols
(b) (i) to increase the rate of reaction ignore references 1
to
dissolving/solubillty

(b) (ii) (copper(II) oxide/it) stops Accept stops 1

disappearing/ stays as a solid / forms dissolving / forms
as a solid (at the bottom of the a suspension
beaker) /forms a residue

Accept when
copper oxide
remains/settles in
the beaker
Allow liquid goes
cloudy/black

ignore references
to stops reacting
ignore references
to bubbling

(iii) a drop of solution forms crystals when Accept when 1

removed (and cooled) crystals start to
form/start to be
seen

Reject if all water

evaporated
(iv) (stage) 3 accept any 1
reference to first
filtration stage

Classified Chemistry 2C - Edexcel Dr.Ann Mahdy

8.ACID , BASES AND SALT PREPARATION 224

Question
Answer Notes Marks
number
14 (a) titration / volumetric analysis 1

(b) C (25 cm3 pipette) 1

(c) M1 (before) – yellow 2

M2 (after) - orange accept pink / red and

combinations with
orange
Allow 1 mark if correct
colours reversed
(d) after adding 23.60 3
acid If readings are correct
before adding but in the wrong
acid 2.75 order, award 1 mark
volume added 20.85 for M1 and M2

M1 23.60
M2 2.75
M3 20.85 M3 CQ on (M1 – M2)

(e) (i) 22.90 22.60 22.45 22.55 1

  

(ii) M1 (22.60 + 22.45 + 22.55) ÷ 3 Correct final answer

with no working scores 2
(2)
M2 22.53 (cm3) Accept 22.53 with 3
recurring

If no results ticked in
(i), then only use of
two or three
concordant titres can
score in (ii)

If only one result

ticked, then no marks
can be scored in (ii)
Otherwise, both marks
CQ on ticked results in
(e)(i)

Answer with zero as

2nd dp does not need
trailing zero

Classified Chemistry 2C - Edexcel Dr.Ann Mahdy

 Answers obtained by
averaging other titre
values do require
answers to 2 dp

Question
Answer Notes Marks
number

15 a M1 (step 1) nitric acid ACCEPT sulfuric acid should be used

Classified Chemistry
3
M2 (step 2) magnesium carbonate is insoluble / magnesium REJECT the use of reagents that
carbonate does not form a solution would not work, eg magnesium
chloride

M3 (step 3) boiling off all the water (will not produce a

hydrated salt)
8.ACID , BASES AND SALT PREPARATION

2C - Edexcel
7 b i If both readings are correct but in
M1 (after) 23.80
the wrong order, award 1 mark for
M1 and M2
M2 (before) 2.15
3
M3 (volume added) 21.65 M3 CQ on the values given for M1
and M2

Penalise missing trailing zeros once

only

b ii M1 (the calculated) volume will be higher

M2 because it includes the air (contained in the tip of the 2

225

burette)

Dr.Ann Mahdy
M2 dep on M1
 1
c i ticks in columns 2 and 4

ii M1 26.45 + 26.25 CQ on any combination of ticked

2 results

If no results are ticked then M1 can

Classified Chemistry
only be awarded if the values from
columns 2 and 4 are averaged

If only one column ticked then no

marks can be awarded in (c)(ii) 2

M2 26.35 (cm3) CQ on results averaged

Answers should be to 2dp, except
trailing zero not needed
8.ACID , BASES AND SALT PREPARATION

2C - Edexcel
Correct final answer without working
scores 2
226

Dr.Ann Mahdy
 Question
Answer Notes Marks
number

15 d M1 heat/boil until crystals form in a sample of solution ACCEPT heat/boil to produce a (hot)
that has been removed (and cooled) saturated/concentrated solution
ACCEPT heat until crystals start/begin to
form
ALLOW (heat/boil to) evaporate some of

Classified Chemistry
the water
ALLOW heat/boil to crystallisation point
IGNORE references to filtering before
heating

M2 leave (the solution) to cool (so that crystals form) M2 dep on M1

M3 filter (to obtain crystals) ACCEPT decant/pour off the

3
liquid/(excess)solution for filter
8.ACID , BASES AND SALT PREPARATION

AND

2C - Edexcel
suitable method of drying crystals eg place in (warm) oven / leave to dry (in
warm place) / use filter paper / use kitchen
towel
REJECT any reference to heating directly
with a flame, eg with a Bunsen
IGNORE reference to washing crystals

M3 dep on M1

If M1 not scored then award 1 mark out of

3 for leaving the solution until the water
evaporates fully
227

Dr.Ann Mahdy