Enthalpy Definitions

Question 1

Enthalpy of formation

Answer 1

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

Question 2

Ionisation enthalpy

Answer 2

the amount of energy required to remove an electron from a gaseous atom of an element to form a gaseous ion under standard conditions

Always endothermic

Question 3

Enthalpy change of atomisation

Answer 3

enthalpy change when 1 mole of gaseous atoms is formed from its element under standard conditions

Endothermic

Question 4

Bond enthalpy

Answer 4

The amount of energy required to break one mole of a specific covalent bond in the gas phase

Question 5

Lattice enthalpy

Answer 5

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

Question 6

Enthalpy of solution

Answer 6

The standard enthalpy change of solution (ΔHsol) is the enthalpy change when 1 mole of an ionic substance dissolves in sufficient water to form an infinitely dilute solution

Question 7

Enthalpy of hydration

Answer 7

The standard enthalpy change of hydration (ΔHhyd) is the enthalpy change when 1 mole of a specified gaseous ion dissolves in sufficient water to form an infinitely dilute solution