Definitions

Question 1

Standard enthalpy of formation

Answer 1

Enthalpy change when one mole of a compound is formed from its elements with all substances in standard states under standard conditions

Question 2

Standard enthalpy of combustion

Answer 2

Enthalpy change for one mole of a substance is burned completely in excess oxygen under standard conditions with all substances in standard states

Question 3

Enthalpy of neutralisation

Answer 3

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

Question 4

1st Ionisation enthalpy

Answer 4

Enthalpy change when one mole of gaseous atoms each lose an electron to form one mole of gaseous 1+ ions

Question 5

Electron affinity

Answer 5

Enthalpy change when one mole of gaseous atoms each gain an 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

Enthalpy of solution

Answer 7

Enthalpy change when one mole of an ionic solid dissolves in water to form a solution of infinite dilution

Question 8

Enthalpy of hydration

Answer 8

Enthalpy change when one mole of gaseous ions dissolves in water (becomes hydrated)

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 an ionic solid is formed from its constituent ions in the gas phase

Question 11

Lattice enthalpy of dissociation

Answer 11

Enthalpy change when one mole of an ionic solid 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 gas

Question 13

Enthalpy of fusion

Answer 13

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

Question 14

Standard conditions

Answer 14

100kPa and a given temp (ie: 298K). Represented by theta

Question 15

Standard states

Answer 15

State substance is in when under standard conditions

Question 16

Enthalpy change

Answer 16

Heat energy change during a reaction under constant pressure

Question 17

Why might mean bond enthalpy be inaccurate

Answer 17

Data quoted is not specific to the bond as it’s from a range of compounds