AQA GCSE Combined Science: Trilogy Chemistry Paper 2 (Foundation), 2023: Question 2
15 marks · Standard Demand difficulty · Short Answer
Analyze the composition and evolution of the Earth's atmosphere, including greenhouse gases, human impact through deforestation and emissions, and resource management strategies.
Practise this questionQuestion
Question text
02 The Earth’s atmosphere is always changing.
02.1 Gases in the Earth’s early atmosphere caused changes on the Earth.
Draw one line from each change to the gas that caused the change.
[2 marks]
Gas that caused the
Change
change
Ammonia
Oceans formed Carbon dioxide
Nitrogen
Sedimentary rocks formed
Oxygen
7 Water vapour
Table 1 shows the percentage of some gases in the atmospheres of
Earth and Mars today.
Table 1
Percentage of gas in atmosphere (%)
Gas
Earth Mars
Argon 0.90 1.9
Carbon dioxide 0.04 95
Nitrogen 78 2.6
Oxygen 21 0.20
02.2 Which gas has the highest percentage in the Earth’s atmosphere?
[1 mark]
02.3 Calculate how many times more carbon dioxide there is in the atmosphere of Mars
than in the atmosphere of Earth.
Use Table 1.
Give your answer in standard form.
[3 marks]
Number of times more carbon dioxide (in standard form) =
Carbon dioxide is a greenhouse gas.
02.4 Figure 1 shows the concentration of carbon dioxide in the Earth’s atmosphere
from 1960 to 2020.
*07* Figure 1
How has the concentration of carbon dioxide in the Earth’s atmosphere changed
from 1960 to 2020?
[1 mark]
Tick ( ) one box.
Decreased
Stayed the same
Increased 9
02.5 Cars emit carbon dioxide.
A car emits 17.2 kg of carbon dioxide on a journey.
There are four people in the car.
Calculate the mass of carbon dioxide emitted per person.
[2 marks]
Mass of carbon dioxide = kg
02.6 Planting trees helps to reduce climate change, because trees use carbon dioxide from
the Earth’s atmosphere.
Name the process in trees which uses carbon dioxide.
[1 mark]
02.7 Figure 2 shows the annual change in forest area in four different parts of the world.
Figure 2
Give two conclusions about the annual change in forest area.
[2 marks]
02.8 Methane is a greenhouse gas.
Figure 3 shows sources of methane emissions.
Figure 3
Determine the percentage (%) of methane emissions from landfill.
[1 mark]
Percentage = %
02.9 Figure 4 shows two ways (A and B) of preventing used items going to landfill.
Figure 4
Name A and B.
Choose answers from the box.
[2 marks]
recycle reduce release reuse reverse
A
B
Mark scheme
Show the mark scheme
Question 2
AO /
Question Answers Mark
Spec. Ref.
02.1 AO1
5.9.1.2
do not accept more than one line from a box on the left
AO /
Question Answers Extra information Mark
Spec. Ref.
02.2 nitrogen 1 AO2
5.9.1.1
AO /
Spec. Ref.
02.3 (number of times more =) AO2
95 5.9.1.1
0.04
= 2375 1
= 2.375 × 103 allow a correctly calculated 1
answer in standard form from an
incorrect calculation which uses
– OMBINED SCIENCE: TRIvalues given inTable 1LOGY – –
AO /
Spec. Ref.
02.4 increased 1 AO2
5.9.2.2
AO /
Spec. Ref.
02.5 (mass CO2 =) AO2
17.2 5.9.3.1
= 4.3 (kg) 1
AO /
Spec. Ref.
02.6 photosynthesis 1 AO1
5.9.1.4
AO /
Spec. Ref.
02.7 any two from: 2 AO2
(forest area) 5.9.2.2
• increases in Africa
• increases in Europe
• decreases in South America
• decreases in Asia
AO /
Spec. Ref.
02.8 6 (%) 1 AO2
5.9.2.1
– OMBINED SCIENCE: TRILOGY – 2F – 5.9.2.2
AO /
Spec. Ref.
02.9 (A) reuse 1 AO2
5.10.2.2
(B) recycle 1
Total Question 2 15
How to answer it
The Earth's Atmosphere and Climate Change
This question assesses your knowledge of the evolution of the atmosphere, the composition of gases today, data interpretation from graphs and tables, and mathematical skills including standard form and percentages.
The Early Atmosphere
Correct Matching
- Oceans formed: Draw line to Water vapour
- Sedimentary rocks formed: Draw line to Carbon dioxide
Key Knowledge
The early atmosphere was mostly CO₂ and water vapour. As the Earth cooled, water vapour condensed to form oceans. CO₂ dissolved in the oceans and was "locked up" in carbonate rocks.
Examiner Tip
The question says "Draw one line from each change". If you draw two lines from one box, you will lose the mark for that box even if one of the lines is correct!
Atmospheric Composition & Math
Answers
02.2: Nitrogen (78%)
02.3: 2.375 × 10³
Step-by-Step Calculation (02.3)
- Find CO₂ values from Table 1: Mars = 95%, Earth = 0.04%.
- Divide Mars by Earth: 95 ÷ 0.04 = 2375.
- Convert to Standard Form: Move the decimal 3 places to the left.
- Result: 2.375 × 10³
Common Error: Standard Form
Many students forget the standard form requirement. 2375 is only worth 2 marks. To get the 3rd mark, it must be in the format A × 10ⁿ where A is between 1 and 10.
Greenhouse Gases & Photosynthesis
02.4: Reading Graphs
The line in Figure 1 starts at ~315 and ends at ~410. Because the line goes up, the answer is Increased.
02.5: Mass Per Person
Total CO₂ = 17.2 kg
Total People = 4
17.2 ÷ 4 = 4.3 kg
02.6: Photosynthesis
The process is Photosynthesis. Trees take in CO₂ and release O₂. This is the main way CO₂ was removed from the atmosphere after plants evolved.
Interpreting Bar Charts
Give two conclusions about the annual change in forest area.
Accepted Conclusions (Any two)
- Forest area increases in Africa.
- Forest area increases in Europe.
- Forest area decreases in South America.
- Forest area decreases in Asia.
Examiner Insight
Top-level responses clearly distinguish between "increase" (bars above 0) and "decrease" (bars below 0). Don't just list the numbers; explain what the numbers mean for the forest area.
Methane and Sustainability
02.8: Pie Chart Calculation
Total must equal 100%.
100 - (46 + 29 + 19) = 6%
02.9: Lifecycle Diagram
A: Reuse (The item goes directly back to the user without being broken down).
B: Recycle (The item is sent back to the "Make" stage to be processed into something new).
Diagram Help
If you were asked to draw this: Reuse is a small loop from "Use" back to "Use". Recycle is a larger loop from "Dispose" back to "Make".
Topics
Chemistry · Biology · C9: Chemistry of the Atmosphere · C10: Using Resources · B4: Bioenergetics
Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Chemistry Paper 2 (Foundation), 2023. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.