4.1.1: Enthalpy changes

Question 1

Lattice formation enthalpy

Answer 1

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

Question 2

Lattice dissociation enthalpy

Answer 2

The enthalpy change when 1 mole of a solid ionic compound is completely dissociated into its gaseous ions.

Question 3

Difference between lattice dissociation enthalpy and lattice formation enthalpy

Answer 3

one negative value, one positive value

Question 4

Lattice formation enthalpy

exo or endo?

Answer 4

Exothermic

Question 5

Lattice dissociation enthalpy

exo or endo?

Answer 5

Endothermic

Question 6

Infinitely dilute solution

Answer 6

A solution whose concentration does not change when more liquid is added as it already contains so much solvent.

Question 7

Enthalpy change of formation

Answer 7

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

Question 8

Bond dissociation enthalpy

Answer 8

The enthalpy change when all the bonds of the same type in 1 mole of gaseous molecules are broken.

Question 9

Enthalpy change of atomisation of an element

Answer 9

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

Question 10

Enthalpy change of atomisation of a compound

Answer 10

The enthalpy change when 1 mole of a compound in its standard state is converted to gaseous atoms

Question 11

First ionisation energy

Answer 11

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

Question 12

Second ionisation energy

Answer 12

The enthalpy change when 1 mole of gaseous 2+ ions is formed from 1 mole of gaseous 1+ ions

Question 13

First electron affinity

Answer 13

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

Question 14

Second electron affinity

Answer 14

Enthalpy change when 1 mole of gaseous 2- ions is made from 1 mole of gaseous 1- ions

Question 15

Enthalpy change of hydration

Answer 15

The enthalpy change when 1 mole of aqueous ions is formed gaseous ions

Question 16

Enthalpy change of solution

Answer 16

The enthalpy change when 1 mole of an ionic substance dissolves in enough solvent to form an infinitely dilute solution