A-LevelChemistryChemical energetics9701/12 · Feb/Mar 2020 · Q41 Mark

The following data are needed for this question. NaHCO3(s) + HCl(aq) → NaCl(aq) + H2O(l) + CO2(g) ΔH = -38.97 kJ mol-1 Na2CO3(s) + 2HCl(aq) → 2NaCl(aq) + H2O(l) + CO2(g) ΔH = -96.59 kJ mol-1 On heating, sodium hydrogencarbonate decomposes as shown. 2NaHCO3(s) → Na2CO3(s) + H2O(l) + CO2(g) What is the enthalpy change for this decomposition?

A-57.62 kJ mol-1

B-18.65 kJ mol-1

C18.65 kJ mol-1

D57.62 kJ mol-1

✓ Correct answer

C: 18.65 kJ mol-1

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Topic: Chemical energetics, A-Level Chemistry (syllabus 9701). Multiple choice, 1 mark.
Source: A-Level Chemistry, Feb/Mar 2020 Paper 1 Variant 2, question 4.

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