1 (a) Describe a chemical test which shows the presence of water.

test .......................................................................................................................

colour change if water is

present ...............................................................................................
........................................................................................................................................
[3]

(b) How could you show that a sample of water is pure?

.......................................................................................................................................[1]

(c) Describe how water is treated before it is supplied to homes and industry.

........................................................................................................................................

................................................................................................................................... [2]

(d) State two industrial uses of water.

........................................................................................................................................

.................................................................................................................................... [2]

[Total: 8]

PhysicsAndMathsTutor.com
2 (a) Water is needed for industry and in the home.

(i) Rain water is collected in reservoirs. How is it treated before entering the water supply?

.............................................................................................................................................

....................................................................................................................................... [2]

(ii) State two industrial uses of water.

.............................................................................................................................................

....................................................................................................................................... [2]

(iii) State two uses of water in the home.

.............................................................................................................................................

....................................................................................................................................... [1]

(b) In many regions, drinking water is obtained by the distillation of sea-water. Explain how
distillation separates the water from sea-water.

....................................................................................................................................................

....................................................................................................................................................

.............................................................................................................................................. [2]

[Total: 7]

PhysicsAndMathsTutor.com
3 The diagram below shows part of the Water Cycle.

cloud
H 2 O(l) H 2 O(g)
Sun
rain

land

H 2 O(l) se a

(a)
a) State the name of each of the following changes of state.

H2O(l) → H2O(g)

name ..........................................................................................................................

H2O(g) → H2O(l)

name ..........................................................................................................................
[2]

(ii) Which one of the above changes of state is exothermic? Explain your choice.

....................................................................................................................................

.............................................................................................................................. [1]

(b) The rain drains into rivers and then into reservoirs. Describe how water is treated before
it enters the water supply.

...........................................................................................................................................

..................................................................................................................................... [2]

(c)
c) Explain how acid rain is formed.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.............................................................................................................................. [4]

PhysicsAndMathsTutor.com
 (ii) Fish live in water which is neutral (neither acidic nor alkaline). Acid rain decreases
the pH of water in lakes and rivers. Both of the bases, calcium oxide and calcium
carbonate, can neutralise this acid and increase the pH. Explain why calcium
carbonate is a better choice.

....................................................................................................................................

.............................................................................................................................. [2]

[Total: 11]

PhysicsAndMathsTutor.com
Ozone is a form of oxygen. Ozone is present in the upper atmosphere and it prevents
dangerous solar radiation from reaching the Earth’s surface. Some of the chemicals that
diffuse into the upper atmosphere decompose ozone. Chemicals that have this effect are
methane (CH4), chloromethane (CH3Cl ) and an oxide of nitrogen (NO2).

(i) Which of these three chemicals diffuses the most slowly? Give a reason for your
choice.

....................................................................................................................................

....................................................................................................................................

.............................................................................................................................. [2]

(ii) Chloromethane is formed when seaweed decomposes. Name the compounds in the
environment from which seaweed might have obtained the following elements:

carbon; .......................................................................................................................

hydrogen; ...................................................................................................................

chlorine. ................................................................................................................ [3]

(iii) How can chloromethane be made from methane?

reagent .......................................................................................................................

condition ............................................................................................................... [2]

PhysicsAndMathsTutor.com
 (iv) The oxides of nitrogen are atmospheric pollutants. Describe how they are formed.

....................................................................................................................................

....................................................................................................................................

.............................................................................................................................. [2]

(v) Complete the equation for the decomposition of ozone.

............... O3 → ...............
[2]

[Total: 11]

PhysicsAndMathsTutor.com
5 (a The major gases in unpolluted air are 79 % nitrogen and 20 % oxygen.

(i) Name another gaseous element in unpolluted air.

[1]

(ii) Name two compounds in unpolluted air.

[2]

(b) Two common pollutants in air are carbon monoxide and the oxides of nitrogen.

(i) Name another pollutant in air.

[1]

(ii) Describe how carbon monoxide is formed.

[2]

(iii) How are the oxides of nitrogen formed?

[2]

(iv) Explain how a catalytic converter reduces the emission of these two gases.

[2]

[Total: 10]

PhysicsAndMathsTutor.com
 This question is concerned with the following oxides.

sulfur dioxide
carbon monoxide
lithium oxide
aluminium oxide
nitrogen dioxide
strontium oxide

(a)
a) Which of the above oxides will react with hydrochloric acid but not with aqueous
sodium hydroxide?

.............................................................................................................................. [1]

(ii) Which of the above oxides will react with aqueous sodium hydroxide but not with
hydrochloric acid?

.............................................................................................................................. [1]

(iii) Which of the above oxides will react with both hydrochloric acid and aqueous sodium
hydroxide?

.............................................................................................................................. [1]

(iv) Which of the above oxides will not react with hydrochloric acid or with aqueous
sodium hydroxide?

.............................................................................................................................. [1]

(b) Two of the oxides are responsible for acid rain.

Identify the two oxides and explain their presence in the atmosphere.

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................

..................................................................................................................................... [5]

PhysicsAndMathsTutor.com
 (c) Lithium oxide is an ionic compound.

(i) Identify another ionic oxide in the list on page 3.

.............................................................................................................................. [1]

(ii) Draw a diagram which shows the formula of lithium oxide, the charges on the ions
and the arrangement of the valency electrons around the negative ion.
Use x to represent an electron from an atom of oxygen.
Use o to represent an electron from an atom of lithium.

[2]

[Total: 12]

PhysicsAndMathsTutor.com
 The diagram shows part of the carbon cycle. This includes some of the processes which
determine the percentage of carbon dioxide in the atmosphere.

carbon dioxide
in the atmosphere

combustion respiration

photosynthesis

(i) Carbon dioxide is one greenhouse gas. Name another one.

.............................................................................................................................. [1]

(ii) Explain the term respiration and how this process increases the percentage of
carbon dioxide in the atmosphere.

....................................................................................................................................

....................................................................................................................................

.............................................................................................................................. [3]

(iii) Explain why the combustion of waste crop material should not alter the percentage
of carbon dioxide in the atmosphere.

....................................................................................................................................

.............................................................................................................................. [2]

(iv) In 1960 the percentage of carbon dioxide in the atmosphere was 0.032% and in
2008 it was 0.038%. Suggest an explanation for this increase.

....................................................................................................................................

.............................................................................................................................. [2]

[Total: 8]

PhysicsAndMathsTutor.com
1 Ammonia is made by the Haber process.

N2(g) + 3H2(g) 2NH3(g)

The forward reaction is exothermic.

Typical reaction conditions are:

• finely divided iron catalyst,

• temperature 450 °C,
• pressure 200 atmospheres.

(a) Explain why the catalyst is used as a very fine powder and larger pieces of iron are not used.

....................................................................................................................................................

....................................................................................................................................................

.............................................................................................................................................. [2]

(b) Using the above conditions, the equilibrium mixture contains about 15% ammonia.

State two changes to the reaction conditions which would increase the percentage of
ammonia at equilibrium.

....................................................................................................................................................

....................................................................................................................................................

.............................................................................................................................................. [2]

(c) Suggest why the changes you have described in (b) are not used in practice.

....................................................................................................................................................

....................................................................................................................................................

.............................................................................................................................................. [2]

[Total: 6]

PhysicsAndMathsTutor.com
 Plant growth is improved by the availability of essential elements, such as nitrogen, and by the soil
having a suitable pH.

(a) Nitrogen-based fertilisers are made from ammonia. Ammonia is manufactured by the Haber
process.

(i) Describe the Haber process giving reaction conditions and a balanced equation.
(Do not discuss reaction rate and yield.)

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

....................................................................................................................................... [5]

(ii) Fertilisers contain nitrogen.

Name the other two elements essential for plant growth commonly found in fertilisers.

....................................................................................................................................... [2]

(b) Crops do not grow well if the soil is too acidic.

(i) One cause of acidity in soil is acid rain. Explain how acid rain is formed.

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

....................................................................................................................................... [3]

(ii) Name two bases which are used to increase the pH of acidic soils.

....................................................................................................................................... [2]

[Total: 12]

PhysicsAndMathsTutor.com
 The reactivity series shows the metals in order of reactivity.

(a) The reactivity series can be established using displacement reactions. A piece of zinc is
added to aqueous lead nitrate. The zinc becomes coated with a black deposit of lead.

Zn + Pb2+ → Zn2+ + Pb

Zinc is more reactive than lead.

The reactivity series can be written as a list of ionic equations.

...... → ...... + ...... most reactive metal : the best reductant (reducing agent)
Zn → Zn 2+
+ 2e –

Fe → Fe2+ + 2e–
Pb → Pb2+ + 2e–
Cu → Cu2+ + 2e–
Ag → Ag+ + e–

(i) In the space at the top of the list, write an ionic equation for a metal which is more
reactive than zinc. [1]

(ii) Write an ionic equation for the reaction between aqueous silver(I) nitrate and zinc.

.............................................................................................................................. [2]

(iii) Explain why the positive ions are likely to be oxidants (oxidising agents).

.............................................................................................................................. [1]

(iv) Deduce which ion is the best oxidant (oxidising agent).

.............................................................................................................................. [1]

(v) Which ion(s) in the list can oxidise lead metal?

.............................................................................................................................. [1]

PhysicsAndMathsTutor.com
 (b) A reactivity series can also be established by measuring the voltage of simple cells. The
diagram shows a simple cell.

voltmeter
V

cadmium copper
electrode electrode

sulfuric acid

Results from cells using the metals tin, cadmium, zinc and copper are given in the table
below.

electrode 1 electrode 2
cell voltage / volts
positive electrode negative electrode

1 copper cadmium 0.74

2 copper tin 0.48
3 copper zinc 1.10

Write the four metals in order of increasing reactivity and explain how you used the data
in the table to determine this order.

...........................................................................................................................................

...........................................................................................................................................

..................................................................................................................................... [3]

[Total: 9]

PhysicsAndMathsTutor.com
 Ammonia is manufactured by the Haber process.

N2(g) + 3H2(g) 2NH3(g)

The forward reaction is exothermic.

(a) Describe how the reactants are obtained.

(i) Nitrogen

....................................................................................................................................

.............................................................................................................................. [2]

(ii) Hydrogen

....................................................................................................................................

....................................................................................................................................

.............................................................................................................................. [3]

(b) The percentage of ammonia in the equilibrium mixture varies with temperature and
pressure.

(i) Which pair of graphs, A, B or C, shows correctly how the percentage of ammonia at
equilibrium varies with temperature and pressure?

percentage percentage
pair A NH3 at NH3 at
equilibrium equilibrium

temperature pressure

percentage percentage
pair B NH3 at NH3 at
equilibrium equilibrium

temperature pressure

percentage percentage
pair C NH3 at NH3 at
equilibrium equilibrium

temperature pressure

PhysicsAndMathsTutor.com
The pair with both graphs correct is ................................................................. [1]
 (ii) Give a full explanation of why the pair of graphs you have chosen in (i) is correct.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.............................................................................................................................. [6]

(iii) Catalysts do not alter the position of equilibrium. Explain why a catalyst is used in
this process.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.............................................................................................................................. [2]

[Total: 14]

PhysicsAndMathsTutor.com
 (a) Nitric acid is now made by the oxidation of ammonia. It used to be made from air and
water. This process used very large amounts of electricity.

Air was blown through an electric arc and heated to 3000 °C.

N2(g) + O2(g) 2NO(g) equilibrium 1

nitric oxide

The equilibrium mixture leaving the arc contained 5 % of nitric oxide. This mixture was
cooled rapidly. At lower temperatures, nitric oxide will react with oxygen to form nitrogen
dioxide.

2NO(g) + O2(g) 2NO2 equilibrium 2

Nitrogen dioxide reacts with oxygen and water to form nitric acid.

(i) Suggest a reason why the yield of nitric oxide in equilibrium 1 increases with
temperature.

.............................................................................................................................. [1]

(ii) What effect, if any, would increasing the pressure have on the percentage of nitric
oxide in equilibrium 1? Explain your answer.

....................................................................................................................................

.............................................................................................................................. [2]

(iii) Deduce why equilibrium 2 is only carried out at lower temperatures.

....................................................................................................................................

.............................................................................................................................. [2]

(iv) Complete the equation for the reaction between nitrogen dioxide, water and oxygen
to form nitric acid.

........NO2 + O2 + ............ → ............HNO3 [2]

(v) Ammonia is more expensive than water and air. Suggest a reason why the
ammonia-based process is preferred to the electric arc process.

.............................................................................................................................. [1]

PhysicsAndMathsTutor.com
 (b)
b) Nitric acid is used to make the fertiliser ammonium nitrate, NH4NO3.
What advantage has this fertiliser over another common fertiliser, ammonium sulfate,
(NH4)2SO4?

.............................................................................................................................. [1]

(ii) Plants need nitrogen to make chlorophyll. Explain why chlorophyll is essential for
plant growth.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.............................................................................................................................. [4]

[Total: 13]

PhysicsAndMathsTutor.com
 Ammonia is made by the Haber process.

N2(g) + 3H2(g) 2NH3(g)

(a) State one major use of ammonia.

..................................................................................................................................... [1]

(b) Describe how hydrogen is obtained for the Haber process.

...........................................................................................................................................

...........................................................................................................................................

..................................................................................................................................... [3]

(c) This reaction is carried out at a high pressure, 200 atmospheres.

State, with an explanation for each, two advantages of using a high pressure.

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................

..................................................................................................................................... [5]

(d)
d) What is the difference between an endothermic and an exothermic reaction?

....................................................................................................................................

.............................................................................................................................. [1]

PhysicsAndMathsTutor.com
 (ii) Bond breaking is an endothermic process. Bond energy is the amount of energy
needed to break or form one mole of the bond. Complete the table and explain why
the forward reaction is exothermic.

N N + 3H H 2H N H

bond energy energy change exothermic

bond
kJ / mol kJ or endothermic

N N 944 +944 endothermic

H—H 436 3 436 = +1308
N—H 388

...........................................................................................................................................

..................................................................................................................................... [3]

[Total: 13]

PhysicsAndMathsTutor.com
1 Clean dry air contains mainly nitrogen and oxygen.

(a) Name two other gases that are in clean dry air.

....................................................................................................................................................

.............................................................................................................................................. [2]

(b) Air often contains pollutants.

Identify three common gaseous pollutants in air and state how each of these pollutants are
produced.

pollutant gas 1 ...........................................................................................................................

how it is produced ......................................................................................................................

....................................................................................................................................................

pollutant gas 2 ...........................................................................................................................

how it is produced ......................................................................................................................

....................................................................................................................................................

pollutant gas 3 ...........................................................................................................................

how it is produced ......................................................................................................................

....................................................................................................................................................
[6]

[Total: 8]

PhysicsAndMathsTutor.com
 This question is about compounds of nitrogen.

(a) (i) Describe the Haber Process giving reaction conditions and a chemical equation.
Reference to rate and yield is not required.

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

....................................................................................................................................... [5]

(ii) Give one use of ammonia.

....................................................................................................................................... [1]

(b) The diagram shows the structure of a hydrazine molecule.

H H

N N

H H

Draw the electron arrangement of a hydrazine molecule. Show the outer shell electrons only.

[2]

(c) Hydrazine is a base.

(i) Define the term base.

....................................................................................................................................... [1]

(ii) Complete the chemical equation to show that hydrazine acts as a base when added to
water.

N2H4 + H2O → .............. + .............. [1]

PhysicsAndMathsTutor.com
 (d) Nitrogen dioxide is an atmospheric pollutant.

(i) State one environmental problem caused by nitrogen dioxide.

....................................................................................................................................... [1]

(ii) Explain how oxides of nitrogen, such as nitrogen dioxide, are formed in car engines.

.............................................................................................................................................

....................................................................................................................................... [2]

[Total: 13]

PhysicsAndMathsTutor.com
 (a) Polluted air contains two oxides of carbon and two oxides of nitrogen. A major source
of these pollutants is motor vehicles.

(i) Describe how carbon dioxide and carbon monoxide are formed in motor vehicle engines.

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

....................................................................................................................................... [3]

(ii) State one adverse effect of each of these gases.

.............................................................................................................................................

....................................................................................................................................... [2]

(iii) Nitrogen monoxide, NO, is released by motor vehicle exhausts.

Explain how nitrogen monoxide is formed in motor vehicle engines.

.............................................................................................................................................

....................................................................................................................................... [2]

PhysicsAndMathsTutor.com
(iv) When nitrogen monoxide is released into the atmosphere, nitrogen dioxide, NO2, is formed.

Suggest an explanation why this happens.

....................................................................................................................................... [1]

(b) Predict the possible adverse effect on the environment when this non-metal oxide, NO2, reacts
with water and oxygen.

....................................................................................................................................................

.............................................................................................................................................. [2]

(c) How are the amounts of carbon monoxide and nitrogen monoxide emitted by modern motor
vehicles reduced? Include an equation in your answer.

....................................................................................................................................................

....................................................................................................................................................

.............................................................................................................................................. [3]

[Total: 13]

PhysicsAndMathsTutor.com
 Three common pollutants in the air are carbon monoxide, the oxides of nitrogen, NO and NO2, and
unburnt hydrocarbons. They are all emitted by motor vehicles.

(a) Describe how the oxides of nitrogen are formed.

....................................................................................................................................................

.............................................................................................................................................. [2]

(b) Describe how a catalytic converter reduces the emission of these three pollutants.

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

.............................................................................................................................................. [4]

(c) Other atmospheric pollutants are lead compounds from leaded petrol.
Explain why lead compounds are harmful.

....................................................................................................................................................

.............................................................................................................................................. [1]

[Total: 7]

PhysicsAndMathsTutor.com
 Air is a mixture of gases. The main constituents are the elements oxygen and nitrogen.

(a) (i) Name another element in air.

.............................................................................................................................. [1]

(ii) Give the formula of a compound in unpolluted air.

.............................................................................................................................. [1]

(b) Common pollutants present in air are the oxides of nitrogen and sulfur dioxide.

(i) How are the oxides of nitrogen formed?

....................................................................................................................................

....................................................................................................................................

.............................................................................................................................. [2]

(ii) How is sulfur dioxide formed?

....................................................................................................................................

....................................................................................................................................

.............................................................................................................................. [2]

(iii) These oxides are largely responsible for acid rain.

State two harmful effects of acid rain.

....................................................................................................................................

.............................................................................................................................. [2]

PhysicsAndMathsTutor.com
(c) The percentage of oxygen in air can be determined by the following experiment.

large pile of small pile

copper of copper

gas syringe gas syringe

he at
containing
50 cm 3 of air

The gas syringe contains 50 cm3 of air. The large pile of copper is heated and the air is
passed from one gas syringe to the other over the hot copper. The large pile of copper
turns black. The gas is allowed to cool and its volume measured.

The small pile of copper is heated and the remaining gas passed over the hot copper.
The copper does not turn black. The final volume of gas left in the apparatus is less
than 50 cm3.

(i) Explain why the copper in the large pile turns black.

....................................................................................................................................

.............................................................................................................................. [2]

(ii) Why must the gas be allowed to cool before its volume is measured?

.............................................................................................................................. [1]

(iii) Explain why the copper in the small pile did not turn black.

.............................................................................................................................. [1]

(iv) What is the approximate volume of the gas left in the apparatus?

.............................................................................................................................. [1]

[Total: 13]

PhysicsAndMathsTutor.com
 (a) State a use for each of the following gases.

(i) chlorine ................................................................................................................ [1]

(ii) argon ................................................................................................................... [1]

(iii) ethene .................................................................................................................. [1]

(iv) oxygen ................................................................................................................. [1]

(b) Describe how oxygen is obtained from air.

...........................................................................................................................................

..................................................................................................................................... [2]

[Total: 6]

PhysicsAndMathsTutor.com