This key facts covers Key Facts: Bond Energies within Bond Energies (HT) for GCSE Chemistry. Revise Bond Energies (HT) in Energy Changes for GCSE Chemistry with 25 exam-style questions and 15 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 9 of 15 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
📌 Key Facts: Bond Energies
- Bond energy = energy needed to break 1 mole of a particular bond
- Units are kJ/mol (kilojoules per mole)
- Breaking bonds is ALWAYS endothermic (requires energy)
- Making bonds is ALWAYS exothermic (releases energy)
- If breaking > making: reaction is endothermic, ΔH positive
- If making > breaking: reaction is exothermic, ΔH negative
- Double bonds (C=C, O=O) have higher bond energy than single bonds
- Triple bonds (N≡N) are even stronger
Practice questions for Bond Energies (HT)
Which statement correctly describes the energy change when chemical bonds are broken?
Explain how you would determine, from a bond energy calculation, whether a reaction is exothermic or endothermic.
Quick recall flashcards
What are the units for bond energy?
kJ/mol (kilojoules per mole)
What is bond energy?
The energy needed to break 1 mole of a particular bond