DP Chemistry (first assessment 2025)
Question 22M.2.HL.TZ2.d(i)
| Date | May 2022 | Marks available | [Maximum mark: 1] | Reference code | 22M.2.HL.TZ2.d(i) |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | Calculate | Question number | d(i) | Adapted from | N/A |
d(i).
[Maximum mark: 1]
22M.2.HL.TZ2.d(i)
Calculate the entropy change of reaction, ΔS⦵, in J K−1 mol−1.
[1]
Markscheme
«Δ = 2 × 206.6 – (130.6 + 116.1) =» 166.5 «J K–1 mol–1» ✔
Examiners report
ΔS was well calculated in general except for some inverted calculations or failure to consider the ratios of the reactants.
Syllabus sections
Reactivity 1. What drives chemical reactions? » Reactivity 1.4—Entropy and spontaneity (Additional higher level) » Reactivity 1.4.1—Entropy, S, is a measure of the dispersal or distribution of matter and/or energy in a system. The more ways the energy can be distributed, the higher the entropy. Under the same conditions, the entropy of a gas is greater than that of a liquid, which in turn is greater than that of a solid. Predict whether a physical or chemical change will result in an increase or decrease in entropy of a system. Calculate standard entropy changes, ΔS⦵, from standard entropy values, S⦵.