AQA GCSE Combined Science: Trilogy Chemistry Paper 2 (Foundation), 2022: Question 1

9 marks · Low Demand difficulty · Short Answer

Analyze the composition, evolution, and pollutants of the Earth's atmosphere, including gas tests and data interpretation from graphs.

Practise this question

Question

A multi-part GCSE chemistry question about the Earth's atmosphere. Figure 1 is a bar chart showing the percentage of gases in the atmosphere today, with Nitrogen at 78% and a gap for Oxygen. Figure 2 shows two pie charts comparing the Earth's early atmosphere (95% carbon dioxide, 4% water vapour) with today's atmosphere (78% nitrogen, 21% oxygen). Figure 3 is a line graph showing the concentration of nitrogen oxides in micrograms per cubic metre from 7 am to 6 pm, showing distinct peaks at 9 am and 5 pm.
Question text

01 This question is about the Earth’s atmosphere.

01.1 The Earth’s atmosphere contains 21% oxygen.

Draw the bar for oxygen on Figure 1.

[1 mark]

Figure 1

01.2 What is used to test for oxygen gas?

[1 mark]

Tick ( ) one box.

A burning splint

A glowing splint

Damp litmus paper

Limewater 3

The Earth’s early atmosphere was very different from the Earth’s atmosphere today.

Figure 2 shows the composition of the Earth’s early atmosphere and of the Earth’s

atmosphere today.

Figure 2

01.3 The percentages of nitrogen and oxygen in the Earth’s atmosphere today are different

from the Earth’s early atmosphere.

Complete the sentences.

Choose answers from the box.

Use Figure 2.

Each answer can be used once, more than once or not at all.

[2 marks]

decreased increased stayed the same

Since the Earth’s early atmosphere, the percentage of nitrogen in the Earth’s

atmosphere has .

Since the Earth’s early atmosphere, the percentage of oxygen in the Earth’s

atmosphere has 4 .

01.4 The Earth’s atmosphere today contains a small amount of carbon dioxide.

Why has the percentage of carbon dioxide decreased since the Earth’s

early atmosphere?

[2 marks]

Tick ( ) two boxes.

Dissolved in oceans

Formation of sedimentary rocks

Industrialisation

Respiration

Volcanic activity 5

Oxides of nitrogen are produced when nitrogen reacts with oxygen in car engines.

Figure 3 shows the concentration of oxides of nitrogen in the atmosphere during one

day in a city.

Figure 3

*0041.*5 Which two times have the highest concentrations of oxides of nitrogen in

the atmosphere?

[2 marks]

01.6 Suggest why there are the highest concentrations of oxides of nitrogen at these times.

[1 mark]

Mark scheme

Show the mark scheme The mark scheme for Question 1. It awards 1 mark for drawing a bar at 21% for oxygen. It identifies 'a glowing splint' as the test for oxygen. It states that both nitrogen and oxygen levels have 'increased' since the early atmosphere. For carbon dioxide decrease, it accepts 'dissolved in oceans' and 'formation of sedimentary rocks'. It identifies peak times from the graph as 9 am and 5 pm, attributing them to more vehicles on the road.

Question 1

AO /

Question Answers Extra information Mark

Spec. Ref.

01.1 bar drawn to 21% 1 AO2

5.9.1.1

AO /

Spec. Ref.

01.2 a glowing splint 1 AO1

5.8.2.2

AO /

Spec. Ref.

01.3 (nitrogen) increased 1 AO2

5.9.1.2

(oxygen) increased 1 5.9.1.3

AO /

Spec. Ref.

01.4 dissolved in oceans 1 AO1

5.9.1.2

formation of sedimentary rocks 1 5.9.1.4

AO /

Spec. Ref.

01.5 9 (am) allow 0900 1 AO2

5.9.3.1

5 (pm) allow 1700 1

AO /

Spec. Ref.

01.6 more cars / buses / lorries on 1 AO3

the roads 5.9.3.1

Total Question 1 9

How to answer it

The Evolution and Composition of the Atmosphere

What this question tests

This question assesses your ability to recall the composition of the modern atmosphere, identify chemical tests for gases, interpret data comparing the early and modern atmosphere, and explain how human activity (traffic) contributes to atmospheric pollution.

Part 01.1 & 01.2

Atmospheric Composition and Gas Tests

Correct Answers

  • 01.1: A bar drawn for Oxygen reaching the 21% mark.
  • 01.2: A glowing splint.

Exam Technique

For 01.1, look closely at the scale. Each small square on the y-axis represents 2%. To draw 21%, your line should be exactly half a small square above the 20 line. Always use a ruler for bar charts!

💡 Key Knowledge: Gas Tests

  • Oxygen (O₂): Relights a glowing splint.
  • Hydrogen (H₂): Burns with a "squeaky pop" using a lit splint.
  • Carbon Dioxide (CO₂): Turns limewater cloudy/milky.
  • Chlorine (Cl₂): Bleaches damp litmus paper white.

Part 01.3 & 01.4

Changes Over Time

Correct Answers

01.3: Nitrogen has increased; Oxygen has increased.

01.4: Tick these two boxes:

  • Dissolved in oceans
  • Formation of sedimentary rocks

Reading the Pie Charts

In Figure 2, Nitrogen goes from "Small amounts" to 78%. Oxygen goes from 0% (not listed) to 21%. Both have clearly increased. Don't overthink it—just use the data provided!

❌ Common Errors

In 01.4, many students accidentally tick "Industrialisation" or "Respiration". These processes increase CO₂ levels. The question asks why CO₂ decreased from the early atmosphere. Remember: CO₂ was "locked up" in rocks (like limestone) and dissolved into the newly formed oceans.

Part 01.5 & 01.6

Pollutants and Data Interpretation

Correct Answers

01.5: 9 am and 5 pm (or 09:00 and 17:00).

01.6: There are more cars / buses / lorries on the road (Rush Hour).

Reading Graphs

The "highest concentrations" are the peaks of the graph. Follow the peak down to the x-axis to find the time. Ensure you include "am" or "pm" to be precise.

💡 Key Knowledge: Oxides of Nitrogen

Oxides of nitrogen (NOₓ) are produced in internal combustion engines (car engines). The high temperatures allow nitrogen (N₂) and oxygen (O₂) from the air to react together. This is why the graph peaks during "rush hour" when traffic is highest.

❌ Common Misconception

Nitrogen does not come from the fuel. It comes from the air being drawn into the engine. Only the heat comes from burning the fuel.

Total Marks Available: 9 | Focus: AO1 (Recall) and AO2 (Application of data)

Topics

Chemistry · C9: Chemistry of the Atmosphere · C8: Chemical Analysis

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Chemistry Paper 2 (Foundation), 2022. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.