DP Chemistry (first assessment 2025)

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Question 19M.2.HL.TZ2.g(i)

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Date May 2019 Marks available [Maximum mark: 2] Reference code 19M.2.HL.TZ2.g(i)
Level HL Paper 2 Time zone TZ2
Command term Determine Question number g(i) Adapted from N/A
g(i).
[Maximum mark: 2]
19M.2.HL.TZ2.g(i)

Determine the standard entropy change, in J K−1, for the decomposition of dinitrogen monoxide.

2N2O (g) → 2N2 (g) + O2 (g)

[2]

Markscheme

ΔSθ = 2(Sθ(N2)) + Sθ(O2) – 2(Sθ(N2O))
OR
ΔSθ = 2 × 193 «J mol-1 K-1» + 205 «J mol-1 K-1» – 2 × 220 «J mol-1 K-1»     [✔]

«ΔSθ = +»151 «J K-1»     [✔]

 

Note: Award [2] for correct final answer.

Examiners report

Candidates were able to calculate the ΔS of the reaction, though in some cases they failed to multiply by the number of moles.

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