chem mod5.2 lattice enthalpy/entropy/gibbs free energy

Enthalpy change of formation

Enthalpy change of formation

Energy transferred when 1 mole of a compound is formed from its elements under standard conditions.

Enthalpy of atomisation

Enthalpy change when 1 mole of gaseous atoms is formed from an element in its standard state.

First Ionisation enthalpy

Enthalpy change to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of gaseous ions with a +1 charge.

First Electron affinity

Enthalpy change when 1 mole of gaseous atoms gain 1 mole of electrons to form 1 mole of gaseous ions with a –1 charge.

Second Ionisation enthalpy

Enthalpy change to remove 1 mole of electrons from 1 mole of gaseous 1+ ions to produce 1 mole of gaseous 2+ ions.

Second electron affinity

Enthalpy change when 1 mole of gaseous 1- ions gains one electron per ion to produce gaseous 2- ions.

Lattice Enthalpy

Standard enthalpy change when 1 mole of an ionic crystal lattice is formed from its constituent ions in gaseous form.

Enthalpy of Hydration

Enthalpy change when 1 mole of gaseous ions become aqueous ions.

Enthalpy of solution

Standard enthalpy change when 1 mole of an ionic solid dissolves in water.

Entropy

Measure of the number of ways atoms can share energy quanta, higher entropy means more disorder.

Solids vs

Solids have lower entropies than liquids, which are lower than gases due to their level of disorder.

Increase in disorder

Leads to a positive entropy change, especially during state changes or significant increase in molecules.

Hydration enthalpies

Exothermic enthalpies when water molecules bond to metal ions, influenced by charge density and ion size.

Full picture of solubility

Entropy increases as solid dissolves into ions, leading to more disorder and particle increase.