DP Chemistry (last assessment 2024)
Question 19M.1.hl.TZ2.14
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.1.hl.TZ2.14 |
| Level | hl | Paper | 1 | Time zone | TZ2 |
| Command term | Question number | 14 | Adapted from | N/A |
14.
[Maximum mark: 1]
19M.1.hl.TZ2.14
Methane undergoes incomplete combustion.
2CH4 (g) + 3O2 (g) → 2CO (g) + 4H2O (g)
What is the enthalpy change, in kJ, using the bond enthalpy data given below?
A. [2(1077) + 4(463)] − [2(414) + 3(498)]
B. [2(414) + 3(498)] − [2(1077) + 4(463)]
C. [8(414) + 3(498)] − [2(1077) + 8(463)]
D. [2(1077) + 8(463)] − [8(414) + 3(498)]
[1]
Markscheme
C
Examiners report
Only 70 % of the candidates chose the correct calculation of the enthalpy change using bond enthalpy data. The most commonly chosen distractor (D) reversed the signs.