DP Chemistry (last assessment 2024)

Question 19M.2.sl.TZ1.b(ii)

Date	May 2019	Marks available	[Maximum mark: 2]	Reference code	19M.2.sl.TZ1.b(ii)
Level	sl	Paper	2	Time zone	TZ1
Command term	Sketch	Question number	b(ii)	Adapted from	N/A

b(ii).

[Maximum mark: 2]

19M.2.sl.TZ1.b(ii)

This question is about peroxides.

Hydrogen peroxide decomposes to water and oxygen when a catalyst such as potassium iodide, KI, is added.

2H₂O₂ (aq) $\xrightarrow{{{\text{KI (aq)}}}}$ O₂ (g) + 2H₂O (l)

Additional experiments were carried out at an elevated temperature. On the axes below, sketch Maxwell–Boltzmann energy distribution curves at two temperatures T₁ and T₂, where T₂ > T₁.

[2]

Markscheme

peak of T₂ to right of AND lower than T₁ [✔]

lines begin at origin AND T₂ must finish above T₁ [✔]

Examiners report

The drawing of the two curves at T1 and T2 was generally poorly done.

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Core

Core » Topic 6: Chemical kinetics » 6.1 Collision theory and rates of reaction

Core » Topic 6: Chemical kinetics

Question 19M.2.sl.TZ1.b(ii)

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