DP Chemistry (last assessment 2024)

Question 21M.2.hl.TZ1.d(ii)

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

d(ii).

[Maximum mark: 1]

21M.2.hl.TZ1.d(ii)

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.

Consider the first stage of the reaction.

CH₄(g) + H₂O (g) $⇌$ CO (g) + 3H₂(g)

State one reason why you would expect the value of ΔH calculated from the $∆ H_{f}^{⦵}$ values, given in section 12 of data booklet, to differ from your answer to (d)(i).

[1]

Markscheme

bond energies are average values «not specific to the compound» ✔

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Core

Core » Topic 5: Energetics/thermochemistry » 5.3 Bond enthalpies

Core » Topic 5: Energetics/thermochemistry

Question 21M.2.hl.TZ1.d(ii)

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