DP Chemistry (first assessment 2025)
Question 19M.1A.SL.TZ1.14
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.1A.SL.TZ1.14 |
| Level | SL | Paper | 1A | Time zone | TZ1 |
| Command term | Question number | 14 | Adapted from | N/A |
14.
[Maximum mark: 1]
19M.1A.SL.TZ1.14
What is the enthalpy change of reaction for the following equation?
A. x + y + z
B. −x − y + z
C. x − y − z
D. x − y + z
[1]
Markscheme
D
Examiners report
83 % of candidates answered this Hess Law question correctly. This topic was obviously well covered.
Syllabus sections
Reactivity 1. What drives chemical reactions? » Reactivity 1.2—Energy cycles in reactions » Reactivity 1.2.2—Hess’s law states that the enthalpy change for a reaction is independent of the pathway between the initial and final states. Apply Hess’s law to calculate enthalpy changes in multistep reactions.