Calculation of enthalpy changes of reaction using bond energies
3 marks · EasyState whether bond breaking is exothermic or endothermic.
State whether bond making is exothermic or endothermic.
Explain your answer to part b.
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(a) Endothermic
(b) Exothermic
(c) Energy is released to the surroundings when new bonds are made.
Common mistakes: Confusing exothermic/endothermic for making/breaking bonds
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Bond breaking is endothermic.
B1 (b) · 1 mark · Bond making is exothermic.
B1 (c) · 1 mark · Explains that energy is released to the surroundings when new bonds are made.
Worked solution
a) Bond breaking is endothermic. b) Bond making is exothermic. c) Making bonds releases energy to the surroundings.