Definitions

Question 1

enthalpy of formation

Answer 1

The enthalpy change when 1 mole of a compound is formed from its constituent elements in their standard states under standard conditions

Question 2

Lattice enthalpy of formation

Answer 2

The enthalpy change when 1 mole of a solid ionic compound is formed from its gaseous ions under standard conditions

Question 3

Lattice enthalpy of dissociation

Answer 3

The enthalpy change when 1 mole of solid ionic compound is dissociated into gaseous ions under standard conditions

Question 4

Enthalpy change of dissociation

Answer 4

The enthalpy when 1 mole of a bonds of the same type of molecule in the gaseous state is broken

Question 5

Enthalpy change of the 1st ionisation energy

Answer 5

The enthalpy change when 1 mole of gaseous 1+ ions are made from 1 mole of gaseous atoms

Question 6

Enthalpy of atomisation

Answer 6

The enthalpy change when 1 mole of gaseous atoms is made from an element in its standard state

Question 7

Enthalpy change of dissociation

Answer 7

When 1 mole of bonds of the same type in the gaseous state is broken

Question 8

Enthalpy change of second ionisation

Answer 8

Enthalpy change when 1 mole of gaseous 2+ ions is formed from one mole of gaseous 1+ ions

Question 9

1st electron affinity

Answer 9

Enthalpy change when 1 mole of gaseous 1- ions are made from 1 mole of gaseous atoms

Question 10

2nd electron affinity

Answer 10

Enthalpy change when 1 mole of gaseous 2- ions are formed from 1 mole of gaseous 1- ions

Question 11

Mean bond enthalpy

Answer 11

Mean bond enthalpy is the enthalpy change when one mole of gaseous molecules each breaks a covalent bond to form two free radicals, averaged over a range of compounds”