Question
(a) Sulfur dioxide is a pollutant in the air.
(i) State one source of sulfur dioxide in the air………………………………………………………………………………………………………………………. [1]
(ii) Sulfur dioxide is oxidised to sulfur trioxide in the air.
Oxides of nitrogen act as catalysts for this reaction.
What is meant by the term catalyst?…………………………………………… [1]
(iii) Sulfur trioxide dissolves in rainwater to form acid rain.
Which one of the following pH values could be the pH of acid rain?
Draw a circle around the correct answer.[1]
pH 4 pH 7 pH 9 pH 13
(iv) State one adverse effect of acid rain on buildings.
……………………………………………………………………………………………………………………… [1]
(b) Sulfur dioxide melts at –73 °C and boils at –10 °C.
What is the physical state of sulfur dioxide at –20 °C?
Explain your answer…………………………………………………………………………………………………………………………….. [2]
(c) Excess sulfuric acid reacts with ammonia to make a salt which can be used as a fertiliser.
State the name of the salt formed when excess sulfuric acid reacts with ammonia…………………………………………………………………………………………………………………………….. [1]
(d) The table shows some observations about the reactivity of four metals with dilute sulfuric acid.
Use the information in the table to put the four metals in order of their reactivity. Put the least reactive metal first.
▶️Answer/Explanation
Ans:
(a)(i) burning fossil fuels / volcanoes / heating (sulfide) ores
(a)(ii) substance which speeds up a reaction / substance which increases the rate of reaction
(a)(iii) pH4
(a)(iv) erodes buildings (made of carbonate rocks) / wears away buildings (made of carbonate rocks) / reacts with mortar / corrodes iron
work / corrodes metal
(b) liquid (1)
–20 °C is between the melting and boiling point / –20 °C is above melting point but lower than boiling point (1)
(c) ammonium sulfate
(d) tungsten < nickel < iron < magnesium (2)
if 2 marks not scored 1 mark for one consecutive pair reversed
Question
Coal gas is made by heating coal in the absence of air. The list shows the main gases present in coal gas.
carbon dioxide
carbon monoxide
ethene
hydrogen
methane
nitrogen
(a) (i) Which one of these gases is an alkane?……………………………………………………………………………………………………………………… [1]
(ii) Draw the structure of a molecule of ethene. Show all of the atoms and all of the bonds.[1]
(iii) Describe how aqueous bromine can be used to tell the difference between methane andethene.……………………………………………………………………………………………………………………… [2]
(b) Ethene molecules react with each other to form poly(ethene).
(i) What is the name given to this type of chemical reaction?……………………………………………………………………………………………………………………… [1]
(ii) Which one of the following words describes the ethene molecules in this reaction?
Draw a circle around the correct answer.
elements mixtures monomers polymers[1]
(iii) Poly(ethene) is a non-biodegradable plastic.
What is meant by the term non-biodegradable?……………………………………………………………………………………………………………………… [1]
(iv) Describe one pollution problem caused by non-biodegradable plastics.……………………………………………………………………………………………………………………… [1]
(c) Ethanol can be made from ethene and one other reactant.
● Name the other reactant.………………………………………………………………………………………………………………………………….
● State the conditions needed to make ethanol from ethene.………………………………………………………………………………………………………………………………….………………………………………………………………………………………………………………………………….[3][Total: 11]
▶️Answer/Explanation
Ans:
(a)(i) methane
(a)(ii)
(a)(iii) with methane (aqueous) bromine remains orange (1)
with ethene (aqueous) bromine decolourised (1)
(b)(i) polymerisation / addition
(b)(ii) monomers
(b)(iii) cannot be decomposed by organisms / cannot be broken down by bacteria / cannot be broken down by fungi
(b)(iv) gets stuck in gullets of birds / gets stuck in gullets of animals / blocks drains
(c) steam (1)
high temperature (1)
catalyst (1)
Question
This question is about air.
(a) The pie chart shows the proportions of the main gases in clean, dry air.
(i) Name the gases G and H.[2]
gas G
gas H
(ii) The graph shows how the volume of a sample of gas G changes as temperature increases. The pressure is kept constant.
Describe how the volume of gas G changes as temperature increases.[1]
(iii) There is a small percentage of noble gases in the air.
The noble gases are unreactive.
Explain why the noble gases are unreactive in terms of their electronic structure.[1]
(iv) Describe the arrangement and separation of the particles in a gas.[2]
arrangement
separation
(b) Two of the pollutants in air are oxides of nitrogen and lead compounds.
(i) Give one effect of each of these pollutants on health.[2]
oxides of nitrogen
lead compounds
(ii) Name two other pollutants present in air.
State the source of each of these pollutants.[4]
pollutant 1
source of pollutant 1
pollutant 2
source of pollutant 2 [Total: 12]
Answer/Explanation
Ans:
(a)(i) G is oxygen (1)
H is nitrogen (1)
(a)(ii) volume increases (as temperature increases)
(a)(iii) they have a full outer shell (of electrons) / they have a complete outer shell (of electrons)
(a)(iv) arrangement: irregular / random (1)
separation: far apart (1)
(b)(i) oxides of nitrogen:
breathing difficulties / irritates lungs / irritates eyes / irritates throat / irritates skin / lung problems (1)
lead compounds:
poisonous / toxic / harms nervous system / harms brain (1)
(b)(ii) 1 mark for each correct pollutant and one 1 mark for each correct source e.g.
sulfur dioxide (1)
burning fossil fuels / volcanoes (1)
carbon monoxide (1)
incomplete combustion of carbon containing substance / incomplete combustion of named carbon compound (1)