1
1 The structures of five carbon compounds are shown below.
A B C
H H H H H Br Br
H C C C H C C H C C H
H H H H H H H
D E
H H O
H C H H C C
H H O H
(a) Answer the following questions about these compounds. Each compound may be used once,
more than once or not at all.
(i) Which compound, A, B, C, D or E, is ethanoic acid? .............................................. [1]
(ii) Which two compounds are saturated hydrocarbons?. .................. and. .................. [1]
(iii) Which compound is the main constituent of natural gas?.. ..................................... [1]
(iv) Which compound reacts with steam to form ethanol? .............................................. [1]
(v) Which compound is causing concern as a greenhouse gas? ..... ........................... [1]
(vi) Which two compounds are in the same homologous series?.... .........and.... ......... [1]
(b) Deduce the molecular formula for compound C.
........................................................................................................................................... [1]
(c) Complete the symbol equation for the complete combustion of compound A.
C3H8 + .........O2 → 3CO2 + .........H2O [2]
[Total: 9]
2 Ammonia, NH3, is used to produce nitric acid, HNO3. This happens in a three-stage process.
Stage 1 is a redox reaction.
4NH3 + 5O2 → 4NO + 6H2O
2
(a) Identify what is oxidised in stage 1.
Give a reason for your answer.
substance oxidised .........................................................................................................
reason .............................................................................................................................
........................................................................................................................................... [2]
(b) In this reaction the predicted yield of NO is 512 g. The actual yield is 384 g.
Calculate the percentage yield of NO in this reaction.
percentage yield of NO = .................................. [1]
(c) The equation for the reaction in stage 2 is shown.
2NO + O2 → 2NO2
Which major environmental problem does NO2 cause if it is released into the atmosphere?
...........................................................................................................................................
........................................................................................................................................... [1]
3
(d) The equation for the reaction in stage 3 is shown.
4NO2 + 2H2O + O2 → 4HNO3
Calculate the volume of O2 gas, at room temperature and pressure (r.t.p.), needed to produce
1260 g of HNO3.
Use the following steps.
• Calculate the number of moles of HNO3.
moles of HNO3 = ...................................
• Deduce the number of moles of O2 that reacted.
moles of O2 = ........................................
• Calculate the volume of O2 gas that reacts at room temperature and pressure (r.t.p.).
3
volume of O2 gas = .................................... dm [4]
4
(e) The reaction in stage 3 is exothermic.
4NO2 + 2H2O + O2 → 4HNO3
Complete the energy level diagram for this reaction. Include an arrow that clearly shows the
energy change during the reaction.
4NO2 + 2H2O + O2
energy
progress of reaction
[3]
[Total: 11]
3 Aluminium is extracted from its ore. The ore is converted into pure aluminium oxide, which then
undergoes electrolysis as shown.
+ power –
supply wires
anodes
+ +
cathode
electrolyte
molten aluminium
(a) (i) Name an ore of aluminium.
................................................................................................................................ [1]
(ii) What is meant by the term electrolysis?
................................................................................................................................
................................................................................................................................ [2]
5
(b) Aluminium oxide has a melting point of about 2000 °C, but the electrolysis process operates
at about 900 °C.
(i) Name the compound added to aluminium oxide to reduce the operating temperature.
................................................................................................................................ [1]
(ii) Suggest one benefit to the environment of reducing the operating temperature.
................................................................................................................................
................................................................................................................................ [1]
(iii) Write the ionic half-equation for the reaction taking place at:
the negative electrode (cathode) .........................................................................
the positive electrode (anode). ............................................................................ [4]
(iv) Explain why the anodes need frequent replacement.
................................................................................................................................
................................................................................................................................ [2]
[Total: 11]
4 Ethanoic acid is manufactured by the reaction of methanol with carbon monoxide.
An equilibrium mixture is produced.
CH3OH(g) + CO(g) ⇌ CH3COOH(g)
(a) State two characteristics of an equilibrium.
1 ......................................................................................................................................
2 ...................................................................................................................................... [2]
6
(b) The purpose of the industrial process is to produce a high yield of ethanoic acid at a high rate
of reaction.
The manufacture is carried out at a temperature of 300 °C.
The forward reaction is exothermic.
Use this information to state why the manufacture is not carried out at temperatures:
• below 300 °C
...........................................................................................................................................
• above 300 °C
........................................................................................................................................... [2]
(c) Complete the table using only the words increases, decreases or no change.
effect on the rate of effect on the equilibrium
the forward reaction yield of CH3COOH(g)
adding a catalyst no change
decreasing the pressure
[3]
(d) Suggest which of the following metals is a suitable catalyst for the reaction. Give a reason for
your answer.
aluminium calcium cobalt magnesium potassium
suitable catalyst ..............................................................................................................
reason ............................................................................................................................. [2]
[Total: 9]
5 Chlorine reacts with carbon monoxide to produce phosgene gas, COCl2(g). A catalyst is used.
Cl2(g) + CO(g) ⇌ COCl2(g)
The reaction is exothermic.
7
(a) Explain why the reaction is exothermic in terms of the energy changes of bond breaking and
bond making.
...........................................................................................................................................
...........................................................................................................................................
........................................................................................................................................... [3]
(b)
(i) Complete the energy level diagram for this reaction.
On your diagram show:
• the product of the reaction
• an arrow representing the energy change, labelled ΔH
• an arrow representing the activation energy, labelled ΔA. [3]
Cl 2(g) + CO(g)
energy
progress of reaction
[3]
(ii) State why a catalyst is used.
................................................................................................................................ [1]
[Total: 7]
6 The table gives some information about four different particles, A, B, C and D.
number of number of number of electronic charge
particle
electrons neutrons protons structure on particle
A 11 12 11 2,8,1 0
B 14 11 2,8,1 0
C 18 20 2,8,8 0
D 18 20 17
8
(a) Complete the table. The first row has been done for you. [4]
(b) Give two particles from the table which are isotopes of each other.
........................................................................................................................................... [1]
(c) Element Z is in the same group of the Periodic Table as A and is less reactive than A.
State the identity of element Z.
........................................................................................................................................... [1]
(d) C is unreactive.
Use information from the table to explain why.
........................................................................................................................................... [1]
[Total: 7]
7 The gases Ar, CO2, N2 and O2 are in clean, dry air.
CO, NO, NO2 and SO2 are gases commonly found in polluted air.
(a) What percentage of clean, dry air is N2?
Give your answer to the nearest whole number.
........................... % [1]
(b) Name the process used to separate O2 from clean, dry air.
........................................................................................................................................... [2]
(c) State one major adverse effect of the pollutant SO2.
........................................................................................................................................... [1]
(d) NO and NO2 are produced in car engines.
Describe how oxides of nitrogen form in a car engine.
...........................................................................................................................................
...........................................................................................................................................
........................................................................................................................................... [2]
9
(e) Many cars have catalytic converters in their exhaust systems. In a catalytic converter, most
of the CO and NO formed in a car engine is changed into less harmful products.
Identify these products and state the metal catalyst used.
products ............................................................................................................................
catalyst ............................................................................................................................. [3]
(f) CO is formed from the incomplete combustion of fossil fuels such as methane.
Write a chemical equation to show the incomplete combustion of methane.
........................................................................................................................................... [2]
[Total: 11]
8 Zinc is manufactured from zinc blende. Zinc blende is an ore which consists mainly of zinc sulfide,
ZnS.
(a) Zinc blende is roasted in air. One of the products is zinc oxide.
Name the other product formed in this reaction.
........................................................................................................................................... [1]
(b) Zinc oxide is then converted into zinc.
Zinc oxide and coke, a source of carbon, are heated in a furnace. Hot air is blown into the
furnace.
(i) Give two reasons why coke is needed.
1 ...........................................................................................................................
2 ........................................................................................................................... [2]
(ii) Write a chemical equation for the formation of zinc in the furnace.
................................................................................................................................ [1]
(iii) Zinc has a melting point of 420 °C and a boiling point of 907 °C. The temperature inside
the furnace is 1200 °C.
Explain how this information shows that the zinc produced inside the furnace is a gas.
................................................................................................................................ [1]
(iv) The gaseous zinc is converted to molten zin.
Name this change of state.
................................................................................................................................ [1]
10
[Total: 6]
9 Dilute sulfuric acid is used to make salts known as sulfates.
A method consisting of three steps is used to make zinc sulfate from zinc carbonate.
3 3
step 1 Add an excess of zinc carbonate to 20 cm of 0.4 mol / dm dilute sulfuric acid until the reaction
is complete.
step 2 Filter the mixture.
step 3 Heat the filtrate until a saturated solution forms and then allow it to crystallise.
3
(a) Name a suitable piece of apparatus for measuring 20 cm of dilute sulfuric acid in step 1.
........................................................................................................................................... [1]
(b) State two observations which would show that the reaction is complete in step 1.
1 ........................................................................................................................................
2 ........................................................................................................................................ [2]
(c) Why is it important to add an excess of zinc carbonate in step 1?
........................................................................................................................................... [1]
(d) What is meant by the term saturated solution in step 3?
...........................................................................................................................................
........................................................................................................................................... [2]
(e) The equation for the reaction is shown.
ZnCO3(s) + H2SO4(aq) → ZnSO4(......) + H2O(l) + CO2(g)
Complete the equation by inserting the state symbol for zinc sulfate. [1]
(f) Name another zinc compound which could be used to make zinc sulfate from dilute
sulfuric acid using this method.
........................................................................................................................................... [1]
(g) Suggest why this method would not work to make barium sulfate from barium carbonate and
dilute sulfuric acid.
........................................................................................................................................... [1]
[Total: 9]
11
10 A student wanted to make hydrated iron(II) sulfate crystals, FeSO4•xH2O, by adding excess
iron(II) carbonate to dilute sulfuric acid. The student followed the procedure shown.
step 1 Add dilute sulfuric acid to a beaker.
step 2 Add small amounts of iron(II) carbonate to the dilute sulfuric acid in the beaker until the
iron(II) carbonate is in excess.
step 3 Filter the mixture formed in step 2.
step 4 Heat the filtrate until it is a saturated solution. Allow to cool.
step 5 Once cold, pour away the remaining solution. Dry the crystals between filter papers.
(a) Why must the iron(II) carbonate be added in excess in step 2?
........................................................................................................................................... [1]
(b) State two observations in step 2 that would show that iron(II) carbonate was in excess.
1 ......................................................................................................................................
2 ...................................................................................................................................... [2]
(c) Describe what should be done during step 3 to ensure there is a maximum yield of crystals.
........................................................................................................................................... [1]
(d) A saturated solution is formed in step 4.
Describe what a saturated solution is.
...........................................................................................................................................
........................................................................................................................................... [2]
(e) Name a different compound that could be used instead of iron(II) carbonate to produce hydrated
iron(II) sulfate crystals from dilute sulfuric acid.
........................................................................................................................................... [1]
[Total: 7]
11 The table shows the melting points, boiling points and electrical conductivities of six substances
D, E, F, G, H and I.
melting point boiling point electrical conductivity electrical conductivity
substance
/ °C / °C when solid when liquid
D 1610 2230 non-conductor non-conductor
E 801 1413 non-conductor good conductor
12
F −119 43 non-conductor non-conductor
G 1535 2750 good conductor good conductor
H 114 184 non-conductor non-conductor
I −210 −196 non-conductor non-conductor
Choose substances from the table which match the following descriptions. Each substance may
be used once, more than once or not at all.
(a) Which substance is a liquid at 25 °C
........................................................................................................................................... [1]
(b) Which substance is a gas at 25 °C?
........................................................................................................................................... [1]
(c) Which three substances contain simple molecules?
........................................................................................................................................... [3]
(d) Which substance could be a metal? Give a reason for your answer.
substance .........................................................................................................................
reason ...............................................................................................................................
........................................................................................................................................... [2]
(e) Which substance has a macromolecular structure? Give two reasons for your answer.
substance .........................................................................................................................
reason 1 ............................................................................................................................
reason 2 ............................................................................................................................ [3]
(f) Which substance is an ionic solid? Give one reason for your answer.
substance .........................................................................................................................
reason ...............................................................................................................................
........................................................................................................................................... [2]
[Total: 12]
