DP Chemistry (last assessment 2024)

Question 20N.3.hl.TZ0.13c

Date	November 2020	Marks available	[Maximum mark: 1]	Reference code	20N.3.hl.TZ0.13c
Level	hl	Paper	3	Time zone	TZ0
Command term	Justify, Predict	Question number	c	Adapted from	N/A

[Maximum mark: 1]

20N.3.hl.TZ0.13c

A voltaic cell is made up of nickel and magnesium half-cells.

$Mg (s) | {Mg}^{2 +} (aq) | | {Ni}^{2 +} (aq) | Ni (s)$

(c)

Predict, giving a reason, how an increase in temperature affects the potential of this cell.

[1]

Markscheme

cell potential/ $E$ increases AND increasing temperature favours forward reaction
OR
cell potential/ $E$ increases AND $∆ G$ becomes more negative
OR
cell potential/ $E$ increases AND $R T / n F \ln Q$ becomes more negative ✔

Accept any correct mathematical explanation using the Nernst equation.

Examiners report

This was often gained as an easy subsequent mark for those that scored full marks in (b). The majority approached this problem by applying a mathematical explanation using the Nernst equation.

Syllabus sections

Additional higher level (AHL)

Additional higher level (AHL) » Topic 19: Redox processes » 19.1 Electrochemical cells

Additional higher level (AHL) » Topic 19: Redox processes

Question 20N.3.hl.TZ0.13c

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