DP Chemistry (last assessment 2024)

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Question 18M.3.sl.TZ2.11b

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Date May 2018 Marks available [Maximum mark: 2] Reference code 18M.3.sl.TZ2.11b
Level sl Paper 3 Time zone TZ2
Command term Discuss Question number b Adapted from N/A
b.
[Maximum mark: 2]
18M.3.sl.TZ2.11b

Carbon dioxide is a product of the combustion of petrol.

(b)

Discuss the significance of two greenhouse gases, other than carbon dioxide, in causing global warming or climate change.

[2]

Markscheme

Any two of:

H2O AND «relatively» greater abundance/stable concentration/less effective at absorbing radiation/lower GWP so not much overall effect on global warming/climate change

CH4/N2O/CFCs/SF6/O3/HCFCs AND more effective «than CO2» at absorbing radiation/higher GWP so could contribute to global warming/climate change

PFCs/SF6/NF3/Some CFCs AND have very long life in atmosphere so could contribute «in the future» to global warming/climate change

 

Accept names or formulas.

Accept two different gases with the same effect for [2].

Award [1 max] for identifying the names/formulas of two greenhouse gases.

Accept “greenhouse factor” for “GWP” but not just “greenhouse effect”.

For M3, do not allow “CFC” alone as only some have long lifetimes (eg, CFC-115, CFC-113).

[2 marks]

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