Oxford Revise AQA GCSE Combined Science Foundation | Chapter C13 answers

C13: The Earth’s atmosphere

Question

Answers

Extra information

Mark

AO / Specification reference

01.1

gas A = nitrogen

gas B = oxygen

1

1

AO2

5.9.1.1

01.2

\(
\begin{align}
& \frac{76}{360} \times 100\\
& = 21\%
\end{align}
\)

1

1

AO2

5.9.1.1

01.3

one from:

  • carbon dioxide
  • water vapour
  • Noble Gases (e.g., argon, neon)

1

AO1

5.9.1.1

01.4

third image

1

AO2

5.9.1.2

01.5

Level 3: The descriptions are detailed and accurate. The reasons given are clear and coherent.

5-6

AO1

5.9.1.2

5.9.1.3

5.9.1.4

Level 2: The descriptions are correct, although lacks detail. Reasons are given for some, although these may not be clearly explained.

3-4

Level 1: The descriptions lack clarity and coherence.

1-2

No relevant content.

0

Indicative content

  • from around 2.7 billion years ago, algae and plants produce oxygen
  • by photosynthesis
  • oxygen in the atmosphere increases for one billion years
  • carbon dioxide + water → glucose + oxygen
  • carbon dioxide removed from atmosphere by photosynthesis
  • carbon dioxide involved in formation of sedimentary rocks
  • carbon dioxide involved in formation of fossil fuels
  • when oceans formed, carbon dioxide dissolved in them
  • volcanoes released nitrogen (or bacteria produced nitrogen)
  • nitrogen is unreactive so built up in the atmosphere

02.1

carbon dioxide

methane

water vapour

1

1

1

AO1

5.9.2.1

02.2

short

reflected

long

long/warms

answers must be in this order

1

1

1

1

AO1

5.9.2.1

02.3

one from:

  • cattle farming
  • rice farming/rice plantations
  • burning fossil fuels
  • deforestation

1

AO1

5.9.2.2

03.1

points plotted correctly

line of best fit drawn

1

1

AO2

AO3

5.9.3.1

03.2

average concentration of carbon dioxide in the atmosphere increases with time

1

AO3

5.9.3.1

03.3

  • burning more fossil fuels
  • releases more carbon dioxide into the atmosphere/carbon dioxide that was trapped in the fossils
  • deforestation
  • less trees to remove carbon dioxide from the atmosphere

accept other sensible answers that specifically relate to carbon dioxide in the atmosphere

1

1

1

1

04.1

oxides of nitrogen

1

AO1

5.9.3.1

04.2

incomplete combustion

1

AO1

5.9.3.1

04.3

2C4H10 + 9O2 → 8CO + 10H2O

accept C4H10 + 4.5O2 → 4CO + 5H2O

1

AO2

5.7.1.3

5.9.3.1

04.4

oxides of nitrogen – breathing problems

carbon monoxide – poisoning humans

particulates – global dimming

1

1

1

AO1

5.9.3.2

04.5

sulfur dioxide

accept oxides of nitrogen

1

AO1

5.9.3.2

05.1

A matching diagram that connects compounds to their symbols. Carbon particulates are C. Sulfur dioxide is mapped to S O 2. Nitrogen Oxides is mapped to N O 2.

3

AO1

5.9.3.2

05.2

oxides of nitrogen (or NOx), nitrogen

sulfur dioxide, sulfur

carbon particulates

1

1

1

AO1

5.9.3.1

05.3

sulfur dioxide – acid rain

nitrogen oxides – breathing problems/acid rain

carbon particulates – global dimming

1

1

1

AO1

5.9.3.2

05.4

carbon monoxide is poisonous

it is colourless and odourless, which makes it

hard to notice

1

1

AO1

5.9.3.2

06.1

a gas that contributes to atmospheric warming

1

AO1

5.9.2.1

06.2

methane/water vapour

2

AO1

5.9.2.1

06.4

one from:

  • sea levels rising – coastal/low-lying areas where people live flooded/become uninhabitable
  • increase in extreme weather events – loss of life; damage to property/infrastructure/places where people live; economic effects of rebuilding/repairing
  • changes to the amount and time of rainfall – cause drought and/or flooding; affect growth of crops
  • changes to ecosystems and habitats – decrease in food availability
  • polar ice caps melting – cause rising sea levels/flooding of habitats

one mark for effect

one mark for relevant explanation

accept any other sensible answers

2

AO1

AO3

5.9.2.3

07.1

the amount of greenhouse gases put into the atmosphere by activity

1

AO1

5.9.2.4

07.2

100 × 120 = 12 000 g

1.2 × 104

1

1

AO2

5.9.2.4

07.3

\(
\frac{1.2 \times 10^4}{2} = 6000
\)

accept answer if given in correct standard form 6 × 103

1

AO2

5.9.2.4

07.4

1050 × 120 = 126 000

\(
\frac{126\ 000}{25} = 5040
\)

1

1

AO2

5.9.2.4

07.5

less

less carbon dioxide released per person than by car

1

1

5.9.2.4

07.6

methane

1

AO1

5.9.2.4

07.7

planting trees/carbon capture and storage

answers must be ways that offset carbon footprint, not ways that decrease it.

accept any other sensible answers

1

AO3

5.9.2.4

08.1

carbon dioxide – very small amounts

\(
\begin{align}
& \textrm{oxygen – }\frac{1}{5}\\
& \textrm{nitrogen – }\frac{4}{5}
\end{align}
\)

one mark for two correct answers

two marks for three correct answers

2

AO1

5.9.1.1

08.2

two from:

  • lots of carbon dioxide
  • little oxygen
  • little nitrogen

one mark for each correct answer up to a maximum of two marks

2

AO1

5.9.1.2

08.3

photosynthesis

1

AO1

5.9.1.3

08.4

condensed

dissolved

1

1

AO1

5.9.1.2

08.5

volcanoes (or bacteria)

1

AO1

5.9.1.2

09.1

no direct observations (because so long ago)

1

AO1

5.9.1.2

09.2

Level 3 (5-6 marks): The descriptions of the explanations are detailed and accurate. The reasons given are clear and coherent.

5-6

AO1

5.9.1.2

5.9.1.3

5.9.1.4

Level 2 (3-4 marks): The descriptions of the explanations are correct, although lacks detail. Reasons are given for some, although these may not be clearly explained.

3-4

Level 1 (1-2 marks): The descriptions of the explanations and reasons lacks clarity and coherence.

1-2

No relevant content.

0

Indicative content:

carbon dioxide

  • percentage of carbon dioxide has decreased
  • water vapour from volcanoes condensed to form oceans
  • carbon dioxide dissolved in the oceans
  • removed during formation of fossil fuels
  • removed during formation of sedimentary rocks
  • removed during photosynthesis

oxygen

  • percentage of oxygen increased
  • algae and plants first produced oxygen by photosynthesis
  • about 2.7 million years ago
  • as more algae and plants grew, the percentage of oxygen in the atmosphere increased

09.3

methane

carbon dioxide

accept other correct answers

1

1

AO1

5.9.2.2

09.4

global climate change

accept an effect of global climate change, e.g., rising sea levels, more extreme weather, changes in rainfall, changes to ecosystems, polar ice caps melting

1

AO1

5.9.2.2

10.1

20%

1

AO1

5.9.1.1

10.2

algae and plants living 2.7 billion years ago

began to photosynthesise

carbon dioxide + water → glucose + oxygen

1

1

1

AO1

5.9.1.3

10.3

glowing splint inserted into test tube

splint relights is oxygen is present

1

1

AO1

5.8.2.2

10.4

photosynthesis/formation of sedimentary rocks/formation of fossil fuels/dissolved in oceans

1

AO1

5.9.1.4

11.1

chromatography

1

AO1

5.8.1.3

11.2

C

it has two spots

1

1

AO2

5.8.1.3

11.3

D

1

AO3

5.8.1.3

11.4

drew start line in pen

1

AO3

5.8.1.3

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