Enthalpy change defenitions

Question 1

Enthalpy change of formation

Answer 1

Enthalpy change when 1 mole of a compound is formed from its elements under standard conditions

Question 2

Enthalpy change of combustion

Answer 2

Enthalpy change when 1 mole of a substance is burnt in excess oxygen under standard conditions

Question 3

Enthalpy change of neutralisation

Answer 3

Enthalpy change when 1 mole of water is formed by reacting an acid and an alkali under standard conditions

Question 4

Enthalpy change of atomisation

Answer 4

Enthalpy change when 1 mole of gaseous atoms is formed from its element under standard conditions (endothermic)

Question 5

Enthalpy change of lattice

Answer 5

Enthalpy change when 1 mole of an ionic compound is formed from its gaseous ions under standard conditions

Question 6

Enthalpy change of solution

Answer 6

Enthalpy change of 1 mole of an ionic substance dissolves in water to give a solution of infinite dilution

Question 7

Enthalpy change of hydration

Answer 7

Enthalpy change when 1 mole of gaseous ions dissolves in water to give an infinitely dilute solution