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Question 19N.2.hl.TZ0.c(ii)

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Date November 2019 Marks available [Maximum mark: 3] Reference code 19N.2.hl.TZ0.c(ii)
Level hl Paper 2 Time zone TZ0
Command term Determine Question number c(ii) Adapted from N/A
c(ii).
[Maximum mark: 3]
19N.2.hl.TZ0.c(ii)

Propene is an important starting material for many products. The following shows some compounds which can be made from propene, C3H6.


Propene (C3H6) → C3H7Cl → C3H8O → C3H6O

Determine the enthalpy of combustion of this compound, in kJ mol−1, using data from section 11 of the data booklet.

[3]

Markscheme

bonds broken:
7(C–H) + C–O + O–H + 2(C–C) + 4.5(O=O)
OR
7(414 «kJ mol−1») + 358 «kJ mol−1» + 463 «kJ mol−1» + 2(346 «kJ mol−1») + 4.5(498 «kJ mol−1») / 6652 «kJ» ✔

bonds formed:
6(C=O) + 8(O–H)
OR
6(804 «kJ mol−1») + 8(463 «kJ mol−1») / 8528 «kJ» ✔


«ΔH = bonds broken − bonds formed = 6652 – 8528 =» −1876 «kJ mol−1» ✔

 

NOTE: Award [3] for correct final answer.

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