Enthalpy

Question 0

Define the enthalpy change of neutralisation.

Answer 0

The enthalphy change when one mole of water is formed by the reaction between an acid and a base under standard conditions (always exothermic).

Question 1

Define the enthalpy change of solution.

Answer 1

The enthalpy change when one mole of a solute is dissolved in sufficient solvent that no further enthalpy change occurs on further dilution.

Question 2

Define the enthalpy change of atomisation of an element.

Answer 2

The enthalpy change when one mole of gaseous atoms is formed from an element in its standard state.

Question 3

Define the enthalpy change of hydration.

Answer 3

The enthalpy change when one mole of aqueous ions is formed from gaseous ions.

Question 4

Define the first ionisation enthalpy.

Answer 4

The enthalpy change when one mole of gaseous 1⁺ ions is formed from one mole of gaseous atoms

Question 5

Define lattice enthalpy.

Answer 5

The enthalpy change when one mole of a solid ionic compound is formed from its gaseous ions under standard conditions (it is a measure of ionic bond strength, and it’s always exothermic).