DP Chemistry (last assessment 2024)

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Question 22N.2.hl.TZ0.3d

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Date November 2022 Marks available [Maximum mark: 2] Reference code 22N.2.hl.TZ0.3d
Level hl Paper 2 Time zone TZ0
Command term Determine Question number d Adapted from N/A
d.
[Maximum mark: 2]
22N.2.hl.TZ0.3d

Consider the following reaction:

Cu2+ (aq) + Fe (s) → Fe2+ (aq) + Cu (s)

(d)

Determine the frequency, in s−1, of a photon that will cause the first ionization of copper. Use sections 1, 2 and 8 of the data booklet.

[2]

Markscheme

Alternative 1

«E=745kJmol-1×1mol6.02×1023atoms=» 1.24×10-21 «kJatom-1» ✔

 «E=hv»

«1.24×10-21kJ×1000J1kJ=6.63×10-34Js×v»

 «v=» 1.87×1015  «s-1» ✔

 

Alternative 2

 «E=hv»

 «745×103Jmol-1=6.63×10-34Js×v»

 «v=» 1.12×1039  «s-1mol-1» ✔

 «=1.12×1039s-16.02×1023» =1.87×1015  «s-1» ✔

 

Award [2] for correct final answer.

Examiners report

Whilst many students managed to identify the correct formula and constants to use to convert energy into frequency, quite a few failed to convert the ionization enthalpy from kJ to J, then even more were unable to convert from a molar to an atomic scale.