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Question 19M.2.hl.TZ1.d(i)

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Date May 2019 Marks available [Maximum mark: 2] Reference code 19M.2.hl.TZ1.d(i)
Level hl Paper 2 Time zone TZ1
Command term Calculate Question number d(i) Adapted from N/A
d(i).
[Maximum mark: 2]
19M.2.hl.TZ1.d(i)

This question is about sodium and its compounds.

The Born-Haber cycle for sodium oxide is shown (not to scale).

Calculate values for the following changes using section 8 of the data booklet.


ΔHatomisation (Na) = 107 kJ mol−1
ΔHatomisation (O) = 249 kJ mol−1

1 2 O2(g) → O2- (g):

Na (s) → Na+ (g):

 

 

[2]

Markscheme

1 2 O2(g) → O2- (g)

«ΔHatomisation (O) + 1st EA + 2nd EA = 249 k Jmol−1 − 141 kJmol−1 + 753 kJmol−1 =» «+»861 «kJmol−1»    [✔]

 

Na (s) → Na+ (g)

«ΔHatomisation (Na) + 1st IE = 107 kJmol−1 + 496 kJmol−1 =» «+»603 «kJmol−1»     [✔]

Examiners report

Good performance with typical error being in the calculation for the first equation, ½O2 (g) → O2− (g), where the value for the first electron affinity of oxygen was left out.

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