No.

3/1

Marker Code Student Personal

Identification Number

Pacific Senior Secondary Certificate

CHEMISTRY
2009

QUESTION AND ANSWER BOOKLET

Time Allowed: 3 Hours

1. This Examination Paper consists of TWO sections. ATTEMPT ALL QUESTIONS.
SECTION CONTENT MARKS
A Multiple Choice Questions 40

B Long Answer Questions 160

2. Write your Student Personal Identification Number (SPIN) on the top right hand corner
of this page and at the top of the fold-out flap on the last page.

3. Write all answers to the Multiple Choice questions in the answer sheet on the FOLD-OUT
FLAP on the last page.

4. In SECTION B, write the answers to the questions in the spaces provided in this booklet.

5. Budget your time carefully. Spend no more than 50 minutes on Section A.

NOTE: The symbol M is used for molar mass.

For example, M(Na) = 23 g mol-1 and M(CO2) = 44 g mol-1

A copy of the Periodic Table of the Elements – Sheet No. 3/2 is provided. The table gives the
Symbol, Atomic Number, and the Relative Atomic Mass of the elements. The Groups (columns)
are numbered I, II, III, IV, etc.

Check that this booklet contains pages 2-25 in the correct order and none of these pages is blank.

YOU MUST HAND THIS BOOKLET TO THE SUPERVISOR AT THE END OF THE
EXAMINATION.

TOTAL MARKS
200
 2

SECTION A
(40 marks)

Answer all the questions in this section. Write the LETTERS of the best answers in the
boxes on the fold-out flap provided on the back flap of this booklet. Each question is
worth 2 marks.

1. Which of the following sets lists species with the same electron arrangement?

A. Fe, Co, Ni.

B. Mg, Ca, Sr.
C. S2–, Cl–, K+.
D. Mg2+, Ca2+, Sr2+

2. The chemical identity of an element is determined by

A. its atomic mass.

B. the number of its protons.
C. the number of its neutrons.
D. the number of its electrons.

3. When combining with non-metallic atoms, metallic atoms generally will

A. lose electrons and form negative ions.

B. lose electrons and form positive ions.
C. lose electrons and increase ionic nuclei.
D. lose electrons and become more negatively charged.

4. Which of these Group 2 oxides has the greatest percent by mass of oxygen?

A. Barium oxide.
B. Calcium oxide.
C. Beryllium oxide.
D. Magnesium oxide.

5. A student wishes to prepare approximately 100 millilitres of an aqueous solution of 6 molL–1 HCl
using 12 molL–1 HCl. Which procedure is correct?

A. Adding 50 mL of 12 molL–1 HCl to 50 mL of water while stirring the mixture steadily.

B. Adding 50 mL of water to 50 mL of 12 molL–1 HCl while stirring the mixture steadily.
C. Adding 50 mL of 12 molL–1 HCl to 50 mL of water and then stirring the mixture steadily.
D. Adding 50 mL of water to 50 mL of 12 molL–1 HCl and then stirring the mixture steadily.

6. What is the total number of atoms contained in 2.00 moles of Ne?

A. 20.18.
B. 40.26.
C. 6.02 x 1023.
D. 1.2 x 1024.
 3

7. If 180 mg of solid glucose (C6H12O6) is dissolved in water to form 200 mL of glucose solution,
what is its concentration in g L-1?

A. 3600
B. 90
C. 0.9
D. 0.09

8. An example of a good electrolyte is

A. CuCl2 (aq).
B. CH3OH (aq).
C. C6H12O6 (aq).
D. HCOOH (aq).

9. The compound, 2-methyl-1-propene, is an isomer of

A. Butane.
B. 1-butene.
C. Propane.
D. Propene.

10. Which polymers occur naturally?

A. Starch and cellulose.

B. Protein and plastic.
C. Protein and nylon.
D. Starch and nylon.

11. The reaction CH2CH2 + H2 → CH3CH3 is an example of

A. Addition.
B. Substitution.
C. Esterification.
D. Fermentation.

12. The general formula of a hydrocarbon with one double covalent bond between adjacent atoms is

A. CnH2n+2.
B. CnH2n.
C. CnH2n+1OH.
D. CnH2n-4.

13. Which compound is most soluble in water?

A. AgCl.
B. Ag2CO3.
C. BaCl2.
D. BaCO3.
 4

14. The most acidic oxide in nature is

A. magesium oxide.
B. aluminium oxide.
C. sodium oxide.
D. sulfur dioxide.

15. As the hydrogen ion concentration of an aqueous solution increases, the hydroxide ion
concentration of this solution will

A. increase.
B. decrease.
C. not change.
D. be equal to 1.0 x 10 –14.

16. When a catalyst is added to a system, a decrease occurs in the

A. heat of reaction.
B. activation energy.
C. potential energy of the reactants.
D. potential energy of the products.

17. A property of a reaction that has reached equilibrium is

A. the amount of products is equal to the amount of reactants.

B. the amount of products is greater than the amount of reactants.
C. the rate of the forward reaction is equal to the rate of the reverse reaction.
D. the rate of the forward reaction is greater than the rate of the reverse reaction.

18. Which substance is produced by the Haber process?

A. Aluminium metal.
B. Ammonia gas.
C. Sulfuric acid.
D. Nitric acid.
 5

19. Given the redox reaction:

2I – (aq) + Br2 (l) → 2Br –(aq) + I2 (s)

Which of the following occurs during the reaction?

A. The I – ion is oxidized, and its oxidation number increases.

B. The I – ion is oxidized, and its oxidation number decreases.
C. The I – ion is reduced, and its oxidation number increases.
D. The I – ion is reduced, and its oxidation number decreases.

20. Which quantities are conserved in all oxidation-reduction reactions?

A. Charge only.
B. Mass only.
C. Both charge and mass.
D. Neither charge nor mass.
 6

SECTION B
(60 marks)

Answer ALL SIX questions (21 - 27) in the spaces provided. If you are
unable to calculate a value for a question and need that value in a later
question, select a convenient value and use where needed.

QUESTION 21 (24 marks)

A. 1. The diagram shows part of the Periodic Table of Elements.

For each of the following write the symbols for ONE element which

(i) is most electronegative. _______________________________________________ (1 mark)

(ii) has six electrons in its outer most shell. ___________________________________ (1 mark)

(iii) has an electron configuration of 1s2 2s2 2p6 3s2 3p6 4s1. ______________________ (1 mark)
39 40
2. Potassium, K, exists as K, K and 41K.

(i) Write the name given to the different forms of potassium element. ______________ (1 mark)
41
(ii) How many protons are in an atom of K? _________________________________ (1 mark)
41
(iii) Write the symbol for an ION of K. ______________________________________ (1 mark)

3. Draw Lewis diagrams (electron dot) for:

(i) Tetrachloromethane (CCl4). (ii) Nitrogen trichloride (NCl3).

(2 marks)

P6 8
 7

(iii) Complete the following table about the bonding of the two compounds above.

Compound Distribution of electron Shape of molecule Polarity of molecules

pairs around central atom

CCl4 a) ____________________ Tetrahedral b) __________________

NCl3 Tetrahedral c) _________________ d) __________________

(4 marks)
(iv) Explain how the shape of NCl3 is determined.

________________________________________________________________________________

________________________________________________________________________________
(2 marks)
(v) Give reasons for the polarity of each molecule.

CCl4___________________________________________________________________ (1 mark)

NCl3___________________________________________________________________ (1 mark)

B. 1. Complete the table (the first one is done for you) below by:

(i) Identifying the type of solid from its properties as molecular, ionic, metallic or covalent
network.

(ii) Choosing an example from: iodine, diamond, sodium nitrate and copper.

Melting Conductivity (i) Type of Solid (ii) Example

Point

High Non conductor Covalent network Diamond

High Conductor as solid or liquid a) _________________ b) ________________

Low Non conductor c) _________________ d) ________________

High Non conductor in solid, conduct e) _________________ f) ________________

in molten or in water solution
(6 marks)

P7 14
 8

(iii) Explain why diamond has a high melting point.

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________
(2 marks)

P8 2 Q 21 24
 9

QUESTION 22 (32 marks)

–1
A. 1. An oxide of nitrogen contains 30.43% nitrogen. Its molar mass is 92 g mol .

(i) Calculate its empirical formula.

________________________________________________________________________________

________________________________________________________________________________
(3 marks)
(ii) Give its molecular formula.

_________________________________________________________________________________
(2 marks)
2. Consider the compound called hydrazine, N2H4.
(i) Calculate the mass of 1 mole of hydrazine.

________________________________________________________________________________

________________________________________________________________________________
(2 marks)
(ii) Calculate the mass % of nitrogen in 1 mole of hydrazine.

________________________________________________________________________________

________________________________________________________________________________
(2 marks)

B. 1. In order to analyse a sample of hydrated oxalic acid, the following data was collected: 0.9 g of
anhydrous oxalic acid and 0.36 g of H2O were present. Hydrated oxalic acid has this formula,
(COOH)2.XH2O.

(i) Calculate the moles of anhydrous oxalic acid.

_________________________________________________________________________________

_________________________________________________________________________________
(2 marks)
(ii) Determine the formula of hydrated oxalic acid, (COOH)2. XH2O.

_________________________________________________________________________________
(3 marks)

P9 14
 10

(iii) Write a balanced chemical equation for the burning of anhydrous oxalic acid in oxygen to
produce carbon dioxide and water.

_________________________________________________________________________________

_________________________________________________________________________________
(2 marks)
(iv) If 2.40 g of hydrated oxalic acid were burned, how many grams of water are produced as a
result?

_______________________________________________________________________ (3 marks)

2. 25 mL samples of oxalic acid were titrated against 0.152 molL-1 potassium hydroxide, KOH. On
average 21.6mL of potassium hydroxide was required to reach the endpoint.
(i) Complete the balanced equation for the reaction between oxalic acid and potassium hydroxide.

H2C2O4 + ____ KOH → ____ H2O + _____________

(3 marks)
(ii) Calculate the amount (in moles) of KOH used.

________________________________________________________________________ (1 mark)

(iii) Determine the amount (in moles) of oxalic acid present in the sample.

________________________________________________________________________ (2 marks)

(iv) Calculate the concentration of oxalic acid in molL-1.

________________________________________________________________________ (2 marks)

P 10 13
 11

C. 1. Use the key list to answer the questions given below. Each item may be used more than once.

I. CuSO4.5H2O(s) IV. CuO(s)

Key List:
II. Cu(OH)2(s) V. Cu(NO3) 2 .3H2O(s)
III. CuCO3(s)

(i) From the key list above, identify the compound that on heating would:

a) produce copper oxide; a black solid, and water. ___________________________ (1 mark)

b) turn from blue to white. ______________________________________________ (1 mark)

c) give off nitrogen dioxide; a brown gas. __________________________________ (1 mark)

d) turn from green to black. _____________________________________________ (1 mark)

e) show no apparent change. _____________________________________________ (1 mark)

P 11 5 Q 22 32
 12

QUESTION 23 (24 marks)

A. 1. Lavandulol is found in lavender plants. The formula of lavandulol is shown below.

(i) Circle ONE functional group in this formula and give its name. (1 mark)

Name of functional group: _______________________________________________ (1 mark)

(ii) Circle the word which best describes lavandulol and give a reason for your answer.

SATURATED UNSATURATED

Reason: _____________________________________________________________ (2 marks)

2. Lavandulol can be extracted from lavender flowers using the apparatus shown below. The
lavandulol is carried off in small droplets with the steam. The retort stand is not shown.

(i) State the name of the piece of apparatus labelled A. ____________________________ (1 mark)

(ii) What is the temperature of the water at point X in the diagram? __________________ (1 mark)

B. 1. Petroleum is a complex mixture of hydrocarbons.

(i) What is meant by the term hydrocarbon?

________________________________________________________________________ (1 mark)

P 12 7
 13

(ii) Petrol, oil, candle wax and diesel oil are all mixtures of hydrocarbons. Use this information and
the polarity of these molecules to explain why oil and petrol mix easily to form homogenous
mixture.

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________
(2 marks)

2. Cracking is also a process used to convert large hydrocarbon molecules into smaller molecules. A
hydrocarbon of molecular formula C12H26 is cracked.

(i) Write the formula of ONE Alkane that may be produced. _______________________________
(1 mark)

(ii) Write the formula of the Alkene produced. ___________________________________ (1 mark)

(iii) Describe ONE reagent that can be used to distinguish between an Alkane and an Alkene.

Reagent used: _____________________________________________________________ (1 mark)

Result with Alkane: ________________________________________________________ (1 mark)

Result with Alkene: ________________________________________________________ (1 mark)

3. Ethanol, CH3CH2OH, can be manufactured either from glucose, C6H12O6, or from ethene.

(i) Describe the manufacture of ethanol from glucose and state its chemical equation.

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________
(3 marks)

(ii) Give the name of this process. _____________________________________________ (1 mark)

P 13 11
 14

C. 1. An unsaturated compound A, C3H6, reacts with water under acidic conditions to form two new
products, B and C. Product B undergoes a series of oxidation reactions and forms D. Product D
reacts with a solution of sodium carbonate producing bubbles of gas. Product B reacts with D in the
presence of sulfuric acid and compound E is formed. Compound E has a characteristic smell.

Gas X

(i) Name Gas X. __________________________________________________________ (1 mark)

(ii) Draw the structures for the Compounds B, C, D and E.

Compound Structures

(4 marks)

P 14 5
 15

(iii) What would be observed when Compound B is converted to Compound D using Cr2O72 –/H+?

________________________________________________________________________________
(1 mark)

P 15 1 Q 23 24
 16

QUESTION 24 (22 marks)

A. 1. Palm oil contains the triglyceride with the structure shown below. It is formed from the reaction
of glycerol and palmitic acid.

(i) Draw the structures of glycerol and palmitic acid in the spaces below.

Glycerol Palmitic Acid (2 marks)

(ii) Define the term hydrolysis.

________________________________________________________________________ (1 mark)

(iii) The triglyceride shown above can undergo hydrolysis in acidic or basic conditions. Write the
names of the hydrolysis products in each of these conditions.

Acidic conditions: _____________________________________________________ (1 mark)

Basic Conditions: ______________________________________________________ (1 mark)

2. The structural formulae below shows two different molecules.

MOLECULE 1 MOLECULE 2

CH3CH2CH2COCH3 CH3CH2CH2CH2COH

P 16 5
 17

(i) Name the molecules. 1: ________________________ 2: ________________________

(2 marks)

(ii) Which molecule is produced from an oxidation of pentan-2-ol? __________________________

(1 mark)

(iii) Describe a reagent used to distinguish the two molecules above, and write the observation.

Reagent: _____________________________________________________________ (1 mark)

Observation: __________________________________________________________ (1 mark)

B. 1. Complete each of the following reaction equations by giving the missing organic reactant(s) or
product(s).

a. HBr + CH3CH2CH=CH2 →

____________________________

CH3
b. + → + HBr
H3C C CH2 Br
______________ ________________ CH3

H2O/H+

c. CH3CH = CH2 → OR
Heat __________ ___________

(5 marks)

P 17 10
 18

2. Answer the questions given below with reference to the compounds numbered I to VI.

CH3CH2CHO CH3COCH3 CH3CH2CO2H

I II III

CH3
|
CH3CH2CH2NH2 CH3C(OH)CH3 CH3CH(OH)CH3

IV V VI

(i) Which compound has the molecular formula C3H8O? __________________________________

(1 mark)

(ii) Draw the structure of an isomer of V (not shown) which is a secondary alcohol.

(1 mark)

(iii) Write the name of compound V. ___________________________________________ (1 mark)

(iv) Which compound would dissolve in water giving a solution with pH < 7? __________ (1 mark)

3. Discuss how polyvinyl chloride (PVC) is dangerous to human lives.

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________
(3 marks)

P 18 7 Q 24 22
 19

QUESTION 25 (16 marks)

A. 1. Three solids, sodium, sulfur and aluminium were placed in beakers of water as shown in the
diagram below.

(i) Which beaker shows the reaction of sodium metal? ___________________________ (1 mark)

(ii) Write a balanced chemical equation for the reaction of sodium with water.
________________________________________________________________________ (2 marks)

(iii) The colour of universal indicator in the solution of sodium and water is ___________ (1 mark)

(iv) State which beaker would most likely contain sulfur and give a reason for your answer.

Beaker: ______________________________________________________________ (1 mark)

Reason: ______________________________________________________________ (1 mark)

2. When aqueous barium chloride is mixed with aqueous sodium sulfate, a precipitate forms.

(i) Complete and balance the equation for the above reaction.

BaCl2 (aq) + ________ → BaSO4 (s) + ___ ________

(3 marks)

(ii) Identify the precipitate. __________________________________________________ (1 mark)

(iii) Give the colour of the precipitate. __________________________________________ (1 mark)

P 19 11
 20

3. Complete table below for the identification of ions.

Ion Test Reagent Test Result

Iodide (I –) a) ___________________ b) _____________________

c) _______________ Add dilute acid Effervescence, gas produced

Fe (II) (Fe2+) d) ___________________ Green ppt

Ca2+ e) ___________________ White ppt

(5 marks)

P 20 5 Q 25 16
 21

QUESTION 26 (26 marks)

A. 1. The states of matter are solid, liquid and gas. The diagram below shows how the molecules are
arranged in these three states.

(i) State the name given to the change of state labeled:

A: ______________________ B: ______________________ C: _______________________

(3 marks)

(ii) Which of the changes A, B or C is endothermic? Explain your answer.

________________________________________________________________________________

________________________________________________________________________________
(2 marks)

2. Methane, CH4, is used as a fuel. The complete combustion of methane can be represented by the
equation below.

CH4 + 2O2 → CO2 + 2H2O ∆H = – 890kJ/mol

(i) Calculate the energy released when 4g of methane is completely combusted.

________________________________________________________________________________
(2 marks)

B. 1. The equation for one of the reactions in the conversion of synthesis gas to methanol is:
–1
CO(g) + 2H2(g) → CH3OH(g) ∆H° = – 91 kJ mol

(i) State the conditions of temperature and pressure that would increase the equilibrium yield of
methanol. Explain your answers.

Temperature condition: __________________________________________________ (1 mark)

P 21 8
 22

Explanation: _____________________________________________________________________

________________________________________________________________________________
(2 marks)

Pressure condition: ________________________________________________________ (1 mark)

Explanation: _____________________________________________________________________

________________________________________________________________________________
(2 marks)

(ii) Explain how the temperature and pressure conditions you have specified affect the rate of the
above reaction.

________________________________________________________________________________

________________________________________________________________________________
(2 marks)

2. Reaction rate increases when concentration or temperature is increased.

Using your knowledge of reacting particles, explain why:

(i) increasing concentration increases reaction rate.

________________________________________________________________________________

________________________________________________________________________________
(2 marks)

(ii) increasing temperature increases reaction rate.

________________________________________________________________________________

________________________________________________________________________________
(2 marks)

C. 1. Write the formula of the conjugate acid of NH3.__________________________________ (1 mark)

(i) Write the formula of the conjugate base of H2O._______________________________ (1 mark)

+ –
(ii) Kw = [H3O ][OH ]. Write an equilibrium equation for the reaction represented by this
equilibrium expression.

________________________________________________________________________________
(1 mark)

P 22 14
 23

2. Complete the table below to show the hydronium ion concentration, [H3O+], hydroxide ion
concentration, [OH–], and pH for the three solutions shown.

Kw = 1.00 × 10–14

Solution [H3O+] mol L–1 [OH–] mol L–1 pH

Hydrochloric acid (HCl)

0.0720 a) ____________ 1.14

Sodium hypochlorite (NaOCl) 11.4

b) ___________ c) ____________

Hypochlorous acid (HOCl) 2.24 × 10–11

d) ___________ 3.39

(4 marks)

P 23 4 Q 26 26
 24

QUESTION 27 (16 marks)

A. 1. Sulfur dioxide gas is bubbled through an acidified solution of potassium permanganate.

SO2 (aq) + MnO4 – (aq) → Mn2+ (aq) + SO42 – (aq)

(i) Describe ONE observation from the above reaction.

________________________________________________________________________ (1 mark)

(ii) Identify the reducing agent and justify your answer.

Reducing agent: __________________________________________________________ (1 mark)

Justification: _____________________________________________________________ (1 mark)

(iii) Write a balanced half-equation to show the formation of sulfate ions from sulfur dioxide.

________________________________________________________________________ (1 mark)

(iv) Write a balanced half-equation for the reaction of the permanganate ions.

________________________________________________________________________ (1 mark)

(v) Write a balanced overall ionic equation for the reaction above.

_______________________________________________________________________ (2 marks)

2. Stainless steel is an alloy of iron. It contains iron, other metals and about 0.5 % of carbon.

(i) Define the term alloy.

_______________________________________________________________________ (1 mark)

(ii) State ONE use of stainless steel.

_______________________________________________________________________ (1 mark)

B. 1. Electroplating of iron or steel with other metals, such as tin, (Sn), is very common in many metal
industries. A simplified diagram of the process is given below.

+ Voltage Source
–

P 24 9
 25

(i) Complete the following.

a) The anode is made of __________________________________________________ (1 mark)

b) The cathode is made of _________________________________________________ (1 mark)

c) The electrolyte is a solution of ___________________________________________ (1 mark)

(ii) State the importance of electroplating iron or steel?

_______________________________________________________________________________
(1 mark)

2. Use the list of reaction types to complete the table below. Write the letter of the reaction type.

List: Reduction – Oxidation reaction – R

Decomposition Reaction – D
Acid – Base Reaction – A

Reaction Type of Reaction

heat
a. 2Pb(NO3) 2 → 2PbO + 4NO2 + O2

b. Chemical process by which cells get their energy from the foods that we
consume.

c. Cellular Respiration:

C6H12O6 + O2 → CO2 + H2O + energy

(3 marks)

P 25 7 Q 27 16
 26

(This page has been left blank deliberately.)

 27

Student Personal
Identification Number (SPIN)

ANSWER SHEET
Remember you are to write the letter of the correct answer only.

1. 11.
SECTION B
(Markers Only)
2. 12.

3. 13.

Q 21 24
4. 14.

5. 15. Q 22 32

6. 16.
Q 23 24
7. 17.

Q 24 22
8. 18.

9. 19. Q 25 16

10. 20.
Q 26 26

Q 27 16

SECTION A SECTION B TOTAL

For Section A:

Number
correct x 2 200
40 160