DP Chemistry (last assessment 2024)

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Question 22M.2.hl.TZ1.2b(i)

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Date May 2022 Marks available [Maximum mark: 1] Reference code 22M.2.hl.TZ1.2b(i)
Level hl Paper 2 Time zone TZ1
Command term Calculate Question number b(i) Adapted from N/A
b(i).
[Maximum mark: 1]
22M.2.hl.TZ1.2b(i)

Magnesium is a reactive metal often found in alloys.

Magnesium is sometimes used as a sacrificial anode to protect steel from corrosion.

(b(i))

Calculate the standard potential, in V, of a cell formed by magnesium and steel half-cells. Use section 24 of the data booklet and assume steel has the standard electrode potential of iron.

[1]

Markscheme

Cell potential: «(–0.45 V – (–2.37 V)» = «+»1.92 «V» ✔

Examiners report

Good performance; instead of E° = 1.92 V, answer such as −1.92 V + or −2.82 V showed a lack of understanding of how to calculate E° cell.

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