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Question 19M.2.hl.TZ1.3h

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Date May 2019 Marks available [Maximum mark: 1] Reference code 19M.2.hl.TZ1.3h
Level hl Paper 2 Time zone TZ1
Command term Compare Question number h Adapted from N/A
h.
[Maximum mark: 1]
19M.2.hl.TZ1.3h

This question is about sodium and its compounds.

(h)

An allotrope of molecular oxygen is ozone. Compare, giving a reason, the bond enthalpies of the O to O bonds in O2 and O3.

[1]

Markscheme

bond in O3 has lower enthalpy AND bond order is 1.5 «not 2»    [✔]

 

Note: Accept “bond in ozone is longer”.

Examiners report

Some candidates recognized that ozone had a resonance structure but then only compared bond length between ozone and oxygen rather than bond enthalpy.

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