DP Chemistry (last assessment 2024)

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Question 18M.2.sl.TZ1.c

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Date May 2018 Marks available [Maximum mark: 2] Reference code 18M.2.sl.TZ1.c
Level sl Paper 2 Time zone TZ1
Command term Describe, Outline Question number c Adapted from N/A
c.
[Maximum mark: 2]
18M.2.sl.TZ1.c

Calcium carbide, CaC2, is an ionic solid.

When calcium compounds are introduced into a gas flame a red colour is seen; sodium compounds give a yellow flame. Outline the source of the colours and why they are different.

[2]

Markscheme

«promoted» electrons fall back to lower energy level

energy difference between levels is different

 

Accept “Na and Ca have different nuclear charge” for M2.

[2 marks]

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