1. C1C2C3 01 Air pollution

2. C123 Jan 2012 2 Answer all the questions.
1 The table gives information about dry air from two different places. One is in a town and the other is in the countryside.
gas present
town %
countryside %
argon
1.00
1.00
nitrogen
78.00
78.00
oxygen
20.80
20.96
carbon dioxide
0.04
carbon monoxide
0.10
nitrogen oxides
0.05
Total
100.00
100.00
(a) Work out the percentage (%) of carbon dioxide in the town.
Show your working.
Write your result in the table.
[2]
(b)
(i) The carbon dioxide concentration is higher in the town.
Suggest why.
[2]
(ii) Some of the carbon dioxide in air is used by plants.
What is the name for this process?
Put a ring around the correct answer.
combustion
electrolysis
photosynthesis
polymerisation
respiration
[1]
C123 Jan 2012

3. 3
(c) The nitrogen oxides in the town come from car engines. Describe how nitrogen oxides are made in car engines.
[3] [Total: 8]
C123 Jan 2012
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4. C123 June 2012 2 Answer all the questions.
1 This question is about the gases in the air.
(a) Finish this table to show the percentage of each of the three main gases in the Earth’s atmosphere today.
Percentage in the
Gas
atmosphere
oxygen %
78%
argon %
[2]
(b) Many scientists are worried about the rise in carbon dioxide in the air. One cause of extra carbon dioxide is burning fuels.
Some people grow trees to burn as firewood.
Sue is talking about how growing and burning trees affects the levels of carbon dioxide in the air.
Sue
Growing and burning trees makes no difference to the total amount of carbon dioxide in the air.
C123 June 2012

5. 3
Describe the processes that affect the amount of carbon dioxide in the air when wood burns and when trees grow.
Explain whether you think Sue is correct or not.
The quality of written communication will be assessed in your answer.
[6]
(c) Human activities can pollute the air.
Two of the pollutant gases are carbon monoxide and sulfur dioxide. Describe the harmful effects caused by these two gases.
[3] [Total: 11]
C123 June 2012
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6. C123 Jan 2013 2 Answer all the questions.
1 A town council decided to make drivers pay a charge for each vehicle entering the town on weekdays (Monday to Friday).
The council did this to reduce air pollution. Scientists were asked to see if this did reduce air pollution.
They made measurements for 14 days before the charge was introduced.
They continued to make measurements for 14 days after the charge was introduced.
The scientists recorded the average concentration of particulates in the air for each day.
200
charge introduced
150
particulate
concentration in µg/m3
100 50
weekend
weekend
weekend
weekend
day
(a)
(i) What was the highest particulate concentration measured during the 28 days?
highest particulate concentration =
µg/m3 [1]
(ii) The World Health Organisation limit for particulate concentration is 150 µg/m3. On how many days was the particulate concentration higher than this?
number of days =
[1]
C123 Jan 2013

7. 3
(b)
(i) Was the town council right to introduce the vehicle entry charge?
Use the graph to explain your answer.
[3]
(ii) Suggest why the introduction of the vehicle entry charge caused a change in the particulate concentration in the town centre.
[2]
(c) Complete these sentences about burning hydrocarbons.
Use words from the list.
carbohydrate
carbon dioxide
carbon monoxide
nitrogen
oxygen
water
During the complete combustion of a hydrocarbon the hydrogen burns to
make
and the carbon burns to make
During incomplete combustion some of the carbon does not join with
Instead it forms solid carbon particulates.
[2]
[Total: 9]
C123 Jan 2013
Turn over

8. 16
© OCR 2013