DP Chemistry (last assessment 2024)

Test builder »

Question 22N.1.sl.TZ0.14

Select a Test
Date November 2022 Marks available [Maximum mark: 1] Reference code 22N.1.sl.TZ0.14
Level sl Paper 1 Time zone TZ0
Command term Derive Question number 14 Adapted from N/A
14.
[Maximum mark: 1]
22N.1.sl.TZ0.14

What is the value for enthalpy of formation of methane from the given enthalpies of combustion?

C (s) + O2 (g) → CO2 (g)                               ΔH = −394 kJ mol−1

H2 (g) + 12O2 (g) → H2O (l)                            ΔH = −286 kJ mol−1

CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (l)         ΔH = −891 kJ mol−1

 

A.   (−394 − 286 − 891) kJ mol−1

B.   (−394 − (2 × 286) − 891) kJ mol−1

C.   (−394 − 286 + 891) kJ mol−1

D.   (−394 − (2 × 286) + 891) kJ mol−1

[1]

Markscheme

D

Examiners report

A well answered question. 62% of the candidates used the enthalpies of combustion given to calculate the enthalpy of formation of methane. The question had a strong discrimination between high-scoring and low-scoring candidates.

Syllabus sections