A2 Chemistry 9701 Crash Course - Chemical Energetics Complete Notes

A collection of vocabulary flashcards based on the lecture notes on chemical energetics.

Enthalpy Change (ΔH)

The heat content of a system at constant pressure.

Atomisation Energy (ΔH atom)

The energy needed to convert one mole of a substance from its elements in standard state to gaseous atoms.

Lattice Energy (ΔH lattice)

The energy released when one mole of an ionic compound is formed from its gaseous ions.

Electron Affinity (EA)

The energy change when an electron is added to a neutral atom in the gas phase.

Trends in Electron Affinity

Electron affinity generally becomes more exothermic across a period and less exothermic down a group due to atomic radius and nuclear charge.

Born-Haber Cycle

A thermochemical cycle that describes the formation of an ionic compound from its constituent elements.

Hydration Enthalpy (ΔH hydration)

The enthalpy change when one mole of gaseous ions dissolves in water to form an infinitely dilute solution.

Enthalpy Change of Solution (ΔH sol)

The energy change when one mole of a solute dissolves in a solvent.

Thermal Stability of Group 2 Compounds

Increases down the group due to decreased polarizing power of cations.

Entropy (S)

The measure of disorder or randomness in a system.

Gibbs Free Energy (ΔG)

A thermodynamic quantity representing the amount of usable energy available to do work; used to predict reaction spontaneity.