a)
Methane (CH4 ) is a simple hydrocarbon gas present in the atmosphere or underground as part of natural gas fossil fuel. A group of single-celled organisms, called archaeans, can produce methane by means of different mechanisms.
State the name of the process by which methane is produced.
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b)
Archaeans can produce methane in a range of different environments.
List two of these environments where methane can be produced.
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c)
When methane is released into the atmosphere, it is involved in the following reaction:
Identify the type of reaction that is illustrated above.
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d)
Carbon compounds, such as methane, can become trapped in peat which can be burned as fuel.
Briefly describe how peat is formed.
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a)
Many marine animals, such as mussels and corals, extract carbon from their surroundings to produce hard body parts such as shells.
State the chemical substance that these hard body parts consist of.
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b)
Describe the process by which the hard body parts of marine organisms, such as molluscs and corals, can become a carbon store.
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c)
The following table shows the atmospheric carbon dioxide levels over time.
Year Carbon dioxide concentration / ppm
1960
316
1970
325
1980
338
1990
354
2000
369
2010
387
Calculate the percentage increase in carbon dioxide concentration between 1960 and 2010. Record your answer to one decimal place.
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d)
Atmospheric carbon dioxide levels have shown a dramatic increase since the industrial revolution.
State the main reason for this increase.
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a)
Carbon dioxide is an example of a greenhouse gas.
Define the term 'greenhouse gas'.
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b)
List two other examples of greenhouse gases, other than carbon dioxide.
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c)
The impact of greenhouse gas in the atmosphere can vary considerably.
State two factors that determine the significance of the impact that a greenhouse gas can have.
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a)
Study the diagram below.
i)
State the name of the process illustrated by the diagram.
[1 mark]
ii)
Label the type of radiation represented by A and B in the diagram.
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b)
Greenhouse gases, especially carbon dioxide, have increased in the atmosphere over the past few decades.
State the effect this increase in greenhouse gases will have on global average temperatures.
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List two possible impacts on climate patterns caused by the change in global temperatures described in part (b).
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One mark is available for clarity of communication throughout this question.
a)
Describe the role of autotrophs within the carbon cycle.
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b)
There are several processes in the carbon cycle that increase the levels of carbon dioxide in the atmosphere.
List two of these processes and state how they increase carbon dioxide levels in the atmosphere.
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c)
Increased carbon dioxide levels in the atmosphere are having an effect on ocean chemistry.
Outline the way in which atmospheric carbon dioxide affects the pH of oceans and how this change may impact marine organisms.
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