Hess Law + Born Haber Cycle

Standard enthalpy change of formation

The standard enthalpy of formation is the enthalpy change when one mole of a compound is formed from its elements, in their normal states, under standard conditions.

Standard state conditions (Pressure)

101kPa

Standard state conditions (Temperature)

298K

Standard state conditions (solutions)

1moldm-3

Standard enthalpy change of combustion

The standard enthalpy of combustion is the enthalpy change when one mole of an element or compound is completely burned in oxygen under standard conditions

Hess’ Law

The overall enthalpy change is independent of the route taken

First Ionisation energy

The energy required to remove one mole of electrons from one more of gaseous atoms to produce 1 mole of gaseous ions

Enthalpy of Atomisation

The enthalpy change when one mole of gaseous atoms is formed from the element in its standard state, under standard conditions

First Electron Affinity

The energy released when one mole of gaseous atoms each acquire an electron to form one mole of gaseous ions

Lattice energy of formation

The enthalpy change when one mole of an ionic compound is formed from its gaseous ions under standard conditions