GCSE Chemistry (AQA) chapter 9: Chemistry of the atmosphere MCQs with answers
By Team Megalecture · Updated 4 Nov 2026
22 exam-style questions on Chemistry of the atmosphere, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.
4.9.1 Composition and evolution of the Earth's atmosphere10 questions
4.9.2-4.9.3 Greenhouse gases, climate change and atmospheric pollutants12 questions
Ten Chemistry of the atmosphere questions with answers
Try each one, then open the answer. These ten stay the same; the test draws new ones every time.
1. How is carbon monoxide produced when fuels burn?
A
the fuel burns in a limited supply of oxygen
B
sulfur impurities in the fuel burn in plenty of oxygen
C
nitrogen from the air reacts with oxygen at a high temperature
D
hydrocarbons burn completely in a plentiful supply of air
Show answer
Answer: A. With too little oxygen, carbon is only partly oxidised, giving carbon monoxide and soot. Complete combustion gives carbon dioxide.
2. Sulfur dioxide and oxides of nitrogen are released when fuels burn. What problems do they cause?
A
global dimming and the depletion of the ozone layer
B
acid rain, and breathing problems such as asthma and bronchitis
C
carbon monoxide poisoning and global warming
D
an increase in the ozone layer and a rise in sea level
Show answer
Answer: B. Both gases dissolve in rain to form acids and irritate the lungs. Soot particles cause global dimming.
3. Which is a potential effect of global climate change?
A
a fall in the average temperature of the Earth's surface
B
less flooding as ice sheets and glaciers grow larger
C
a rise in the pH of the oceans because of extra carbon dioxide
D
rising sea levels, which cause flooding and coastal erosion in low-lying areas
Show answer
Answer: D. Warming melts ice and expands sea water, so sea levels rise. Extra CO2 actually lowers ocean pH.
4. 6CO2 + 6H2O → C6H12O6 + 6O2. What mass of carbon dioxide is needed to make 90 g of glucose, C6H12O6? (Ar H = 1, C = 12, O = 16)
A
44 g
B
66 g
C
132 g
D
264 g
Show answer
Answer: C. Mr of glucose = 180, so 90 g = 0.50 mol. The equation needs 6 mol of CO2 for each mole of glucose, so 3.0 mol of CO2 is needed. Mass = 3.0 × 44 = 132 g.
5. Apart from nitrogen and oxygen, which gases make up small proportions of the atmosphere today?
A
hydrogen, helium and sulfur dioxide
B
argon, carbon dioxide and water vapour
C
hydrogen, methane and chlorine in equal amounts
D
ammonia, carbon monoxide and sulfur dioxide
Show answer
Answer: B. The small remaining proportion is mostly argon and other noble gases, carbon dioxide (about 0.04%) and water vapour.
6. Which processes removed carbon dioxide from the early atmosphere?
A
volcanic eruptions and the breaking down of dead plants and animals by microbes
B
combustion of fossil fuels and respiration by the first plants and animals
C
the formation of the ozone layer and the condensation of water vapour into rain
D
photosynthesis and the locking up of carbon in rocks and fossil fuels
Show answer
Answer: D. Plants absorbed CO2; carbonate rocks such as limestone and fossil fuels such as coal locked carbon away. Combustion, respiration and decay release CO2.
7. Which is the word equation for photosynthesis?
A
water + oxygen → glucose + carbon dioxide
B
glucose + oxygen → carbon dioxide + water
C
carbon dioxide + water → glucose + oxygen
D
carbon dioxide + oxygen → glucose + water
Show answer
Answer: C. Photosynthesis uses carbon dioxide and water to make glucose and oxygen. Glucose + oxygen → carbon dioxide + water is respiration, the reverse.
8. According to one theory, how were the oceans formed?
A
water vapour from volcanoes condensed as the Earth cooled
B
nitrogen and oxygen reacted together to form water vapour
C
water was made by plants during photosynthesis and fell as rain
D
water seeped out of sedimentary rocks as the land sank
Show answer
Answer: A. Volcanic activity released water vapour; as the Earth cooled the vapour condensed to form the oceans.
9. Why is it hard to make accurate predictions about climate change?
A
the global climate is very complex, so models must be simplified
B
climate models are all identical, so they give the same prediction
C
temperatures cannot be measured accurately anywhere on Earth
D
there is no data at all on carbon dioxide levels over time
Show answer
Answer: A. Climate involves many interacting factors, so models are simplified and can give different results. This makes it easy to present speculation or biased opinion as fact.
10. Which gases are greenhouse gases?
A
carbon dioxide, methane and water vapour
B
nitrogen, oxygen and argon, the main gases in the air
C
hydrogen, helium and neon, the lightest gases
D
argon, neon and krypton, the noble gases
Show answer
Answer: A. Carbon dioxide, methane and water vapour absorb infrared radiation. Nitrogen and oxygen, the main gases in air, do not.
Chemistry of the atmosphere: questions students ask
How many Chemistry of the atmosphere MCQs are there?
22, each with the answer and a short explanation, across 2 topics: 4.9.1 Composition and evolution of the Earth's atmosphere, 4.9.2-4.9.3 Greenhouse gases, climate change and atmospheric pollutants. Every chapter test draws ten of them, so you can take it many times.
Is the GCSE Chemistry (AQA) chapter 9 test free?
Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.
How is the chapter test marked?
The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.
