Thermodynamics key terms

Question 1

Enthalpy of formation

Answer 1

enthalpy change when 1mol of a substance is formed from its constituent elements with all substances in their standard states

Question 2

Enthalpy of combustion

Answer 2

enthalpy change when 1mol of a substance undergoes complete combustion in Oxygen with all substances in standard states

Question 3

Enthalpy of neutralisation

Answer 3

enthalpy change when 1mol of water is formed in a reaction between an acid and a base under standard conditions

Question 4

1st electron affinity

Answer 4

enthalpy change when each atom in 1mol of gaseous atoms gains 1electron to form 1mol of gaseous 1- ions

Question 5

Enthalpy of atomisation

Answer 5

enthalpy change when 1mol of gaseous atoms is produced from an element in its standard state

Question 6

Hydration enthalpy

Answer 6

enthalpy change when 1mol of gaseous ions become hydrated

Question 7

Enthalpy of solution

Answer 7

enthalpy change when 1mol of an ionic solid dissolves in an amount of water large enough so that the dissolved ions are well seperated and don’t interact with each other

Question 8

Bond dissociation enthalpy

Answer 8

enthalpy change when 1mol of covalent bonds is broken in the gaseous state

Question 9

Lattice enthalpy of formation

Answer 9

enthalpy change when 1mol of a solid ionic compound is formed from its constituent ions in the gas phase (should always be exothermic)

Question 10

Lattice enthalpy of dissociation

Answer 10

enthalpy change when 1mol of a solid ionic compound is broken up into its constituent ions in the gas phase (should always be endothermic)

Question 11

Enthalpy of vapourisation

Answer 11

enthalpy change when 1mol of a liquid is turned into a gas

Question 12

Enthalpy of fusion

Answer 12

enthalpy change when 1mol of a solid is turned into a liquid