DP Chemistry (last assessment 2024)

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Question 21M.2.hl.TZ1.4e(iv)

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Date May 2021 Marks available [Maximum mark: 1] Reference code 21M.2.hl.TZ1.4e(iv)
Level hl Paper 2 Time zone TZ1
Command term Predict Question number e(iv) Adapted from N/A
e(iv).
[Maximum mark: 1]
21M.2.hl.TZ1.4e(iv)

Hydrogen peroxide can react with methane and oxygen to form methanol. This reaction can occur below 50°C if a gold nanoparticle catalyst is used.

Now consider the second stage of the reaction.

CO (g) + 2H2 (g) ⇌ CH3OH (l)          ΔH⦵ = –129 kJ

(e(iv))

Predict, giving a reason, how a change in temperature from 298 K to 273 K would affect the spontaneity of the reaction.

[1]

Markscheme

reaction «more» spontaneous/ΔG negative/less positive AND effect of negative entropy decreases/TΔS increases/is less negative/more positive
OR
reaction «more» spontaneous/ΔG negative/less positive AND reaction exothermic «so Kc increases » ✔

Award mark if correct calculation shown.

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