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Question 21N.2.sl.TZ0.a

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Date November 2021 Marks available [Maximum mark: 2] Reference code 21N.2.sl.TZ0.a
Level sl Paper 2 Time zone TZ0
Command term Determine Question number a Adapted from N/A
a.
[Maximum mark: 2]
21N.2.sl.TZ0.a

Alkanes undergo combustion and substitution.

Determine the molar enthalpy of combustion of an alkane if 8.75 × 10−4 moles are burned, raising the temperature of 20.0 g of water by 57.3 °C.

[2]

Markscheme

«q = mcΔT = 20.0 g × 4.18 J g−1 °C−1 × 57.3 °C =» 4790 «J» ✔

«∆Hc4790 J10008.75×10-4 mol=» –5470 «kJ mol–1» ✔

 

Award [2] for correct final answer.

Accept answers in the range –5470 to –5480 «kJ mol−1».

Accept correct answer in any units, e.g. –5.47 «MJ mol−1» or 5.47 x 106 «J mol−1».

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