Thermochemistry written questions
Solve H1 Chemistry calorimetry, Hess-cycle and bond-enthalpy problems, with written questions and marking guidance for working and signs.
Learning goals
- Explain that most reactions transfer energy, mainly as heat from breaking and forming bonds, and can be exothermic (∆H negative) or endothermic (∆H positive)
- Construct and interpret energy profile diagrams using the enthalpy change and the activation energy
- Explain and use standard enthalpy changes of formation, combustion and neutralisation
- Explain and use bond energy, with ∆H positive for bond breaking
- Explain and use lattice energy, with ∆H negative for gaseous ions forming a solid lattice
- Calculate enthalpy changes from experimental results, using heat change = mc∆T
- Explain how ionic charge and ionic radius affect the size of a lattice energy
- Use Hess' Law and given energy cycles to find enthalpy changes that cannot be measured directly, such as an enthalpy change of formation from enthalpy changes of combustion
- Use Hess' Law with average bond energies to calculate enthalpy changes
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