DP Chemistry (last assessment 2024)

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Question 18N.3.hl.TZ0.5b

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Date November 2018 Marks available [Maximum mark: 3] Reference code 18N.3.hl.TZ0.5b
Level hl Paper 3 Time zone TZ0
Command term Determine Question number b Adapted from N/A
b.
[Maximum mark: 3]
18N.3.hl.TZ0.5b

A representation of the unit cell of gold is shown.

(b)

The edge length of the gold unit cell is 4.08 × 10‒8 cm.

Determine the density of gold in g cm‒3, using sections 2 and 6 of the data booklet.

[3]

Markscheme

«4 atoms per unit cell»

mass of 4 atoms « = 4 × 196.97 g mo l − 1 6.02 × 10 23 mo l − 1 = » 1.31 × 10–21 «g»

volume of unit cell «= (4.08 × 10‒8)3 cm3» = 6.79 × 10–23 «cm3»

density = « 1.31 × 10 − 21 g 6.79 × 10 − 23 c m 3 » = 1.93 × 101/19.3 «g cm‒3»

 

Award [3] for correct final answer.

 

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