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3.2 Energetics

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Question 16
H

Ammonia is made in the Haber process.

N2+3H2⇌2NH3 \mathrm{N_{2} + 3H_{2} \rightleftharpoons 2NH_{3}} N2​+3H2​⇌2NH3​

Each ammonia molecule contains three N−H\mathrm{N{-}H}N−H bonds.

BondN≡N\mathrm{N{\equiv}N}N≡NH−H\mathrm{H{-}H}H−HN−H\mathrm{N{-}H}N−H
Bond energy (kJ/mol\mathrm{kJ/mol}kJ/mol)945436391

What is the energy change for the forward reaction?

[1]
A

+93 kJ/mol+93\,\mathrm{kJ/mol}+93kJ/mol

B

+1080 kJ/mol+1080\,\mathrm{kJ/mol}+1080kJ/mol

C

−965 kJ/mol-965\,\mathrm{kJ/mol}−965kJ/mol

D

−93 kJ/mol-93\,\mathrm{kJ/mol}−93kJ/mol

Markscheme

3.2 Energetics Questions

  1. GCSE
  2. /Chemistry
  3. /3.2 Energetics

51 exam-style questions on OCR GCSE Chemistry 3.2 Energetics, covering 3.2.1 Exothermic and endothermic reactions and reaction profiles and 3.2.2 Calculating energy change from bond energies. Each one has a worked solution and a mark scheme showing where the marks go.

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