DP Chemistry (last assessment 2024)

Question 20N.2.sl.TZ0.b(iii)

Date	November 2020	Marks available	[Maximum mark: 1]	Reference code	20N.2.sl.TZ0.b(iii)
Level	sl	Paper	2	Time zone	TZ0
Command term	Determine	Question number	b(iii)	Adapted from	N/A

b(iii).

[Maximum mark: 1]

20N.2.sl.TZ0.b(iii)

Chlorine undergoes many reactions.

$2.67 g$ of manganese(IV) oxide was added to $200.0 {cm}^{3}$ of $2.00 mol {dm}^{- 3} HCl$ .

${MnO}_{2} (s) + 4 HCl (aq) \to {Cl}_{2} (g) + 2 H_{2} O (l) + {MnCl}_{2} (aq)$

Determine the excess amount, in $mol$ , of the other reactant.

[1]

Markscheme

$« 0.0307 mol \times 4 = 0.123 mol »$

$« 0.400 mol - 0.123 mol = » 0.277 « mol »$ ✔

Examiners report

Half of the candidates were able to determine the amount of excess reactant. Some candidates who determined the limiting reactant in the previous part correctly, forgot to use the stoichiometric ratio in this part, and ended up with incorrect answers.

Syllabus sections

Core

Core » Topic 1: Stoichiometric relationships » 1.3 Reacting masses and volumes

Core » Topic 1: Stoichiometric relationships

Question 20N.2.sl.TZ0.b(iii)

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