Endothermic reactions
3 marks · Easy(a)[1 mark]
Name the term that describes the total heat energy change during a chemical reaction.
(b)[2 marks]
A chemical change absorbed 74 kJ when 2.0 mol of reactant were used. Calculate the enthalpy change, ΔH, in kJ/mol. Show your calculation.
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(a) Enthalpy change (ΔH)
(b) +37 kJ/mol
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States 'enthalpy change' or 'ΔH'.
M1 (b) · 1 mark · Uses formula ΔH = q / n with correct substitution.
A1 (b) · 1 mark · Gives final answer +37 kJ/mol with unit and sign.
Worked solution
a) The term is 'enthalpy change' (ΔH).
b) ΔH = q / n