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Question 19M.3.HL.TZ1.b

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Date May 2019 Marks available [Maximum mark: 1] Reference code 19M.3.HL.TZ1.b
Level HL Paper 3 Time zone TZ1
Command term Identify Question number b Adapted from N/A
b.
[Maximum mark: 1]
19M.3.HL.TZ1.b

Some halophilic bacteria biodegrade benzene, which makes them useful in treating oil spills as benzene is contained in crude oil. Investigators added cultures of the bacteria to benzene solutions at different salinities in containers. The amount of benzene remaining in the container was recorded once a week for two weeks.

[Source: adapted from C A Nicholson and B Z Fathepure, (2004),
Applied and Environmental Microbiology, 70 (2), pages 1222–1225]

Identify the salt concentration with the greatest rate of benzene biodegradation.

………………......… mol m–3

[1]

Markscheme

1 mol m–3 ✔

Examiners report

(a) to (c) These three questions were often answered well.

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