Energetic 2

Question 1

Enthalpy of formation

Answer 1

Enthalpy change when one mole of a substane is formed from its constituent elements wwith all substances in their standard states

Question 2

Enthalpy of combustion

Answer 2

Enthalpy change when one mole of a substance undergoes complete combustion in oxygen with all substances in standard states

Question 3

Enthalpy change of neutralisation

Answer 3

Enthalpy change when 1 mole of water is formed in a reaction between an acid and alkali under standard conditions

Question 4

Ionisation enthalpy:

Answer 4

Enthalpy change when each atom of one mole of gaseous atoms loses one electron to form one mole of gaseous 1+ ions

Question 5

Electron affinity

Answer 5

Enthalpy change when each atom in one mole of gaseous atoms gains one electron to form one mole of gaseous 1- ions

Question 6

Enthalpy of atomisation

Answer 6

Enthalpy change when one mole of gaseous atoms is produced from an element in its standard state

Question 7

Hydration enthaloy

Answer 7

Enthalpy change when one mole of gaseous IONS become hydrated

Question 8

Enthalpy of solution

Answer 8

Enthalpy change when one mole of an ionic solid dissolves in an amount of water large enough so that the dissolved ions are well seperated and do not interact with each other

Question 9

Bond dissociation enthalpy

Answer 9

ENthalpy change when one mole of covalent bonds is broken in the gaseous state

Question 10

Lattice enthalpy of formation

Answer 10

Enthalpy change when one mole of a SOLID ionic compound is formed from its constituent ions in the gas phase

Question 11

Lattice enthalpy of dissociation

Answer 11

Enthalpy change when one mole of a SOLID ionic compound is broken up into its constituent ions in the gas phase

Question 12

Enthalpy of vaporisation

Answer 12

Enthalpy change when one mole of a liquid is turned into a gas

Question 13

Enthalpy of fusion

Answer 13

Enthalpy chnage when one mole of a solid is turned into a liquid

Question 14

What does electrostatic theory assume?
What is this true for?

Answer 14

Ions are spherical
Ions are point charges (Charge is evenly distributed)
Ions are in contact

Pure ionic bonding

Question 15

Why the difference between experimental and theoreticl deltaH ?

Answer 15

A degree of covalency ; the charge cloud is distrorted

(Polarisation of the anion)

Question 16

What are polarising power of the cation and polarisability of the anion dependent on?

Answer 16

Charge and radius

Question 17

Gibbs equation

Answer 17

ΔG = ΔH − TΔSsystem

Question 18

Total entropy equation

Answer 18

ΔStotal = ΔSsystem + ΔSsurroundings

Question 19

Surroundings equation

Answer 19

• ΔH/T