6 x 1 hour lessons

This module builds on your knowledge of energetics by introducing lattice enthalpy, solution processes, and entropy. You'll begin by examining how ionic lattices form and why lattice enthalpies vary based on ion size and charge. You'll learn to construct Born–Haber cycles and use them to calculate enthalpy changes, and you'll apply Hess’ Law to calculate the enthalpy change when an ionic compound dissolves in water using hydration and lattice enthalpies.

The second part of the module focuses on entropy, a measure of the disorder in a system. You’ll explore how entropy changes in chemical reactions, how to calculate ΔS (system) using standard entropy values, and how to reason qualitatively about ΔS (surroundings) ΔS (total). 

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By the end of this module, you’ll be able to:

• Define lattice enthalpy and explain how ionic charge and size affect it

• Construct and interpret Born–Haber cycles

• Calculate enthalpy of solution using hydration and lattice enthalpies

• Define entropy and calculate ΔS (system) from standard values

• Calculate ΔS (surroundings) and ΔS (total)

• Use entropy concepts to predict the feasibility of chemical processes