Enthalpy

Question 1

Standard conditions

Answer 1

298K, 1 bar, (know that there is another condition of ions at 1.0 M but don’t say for enthalpy)

Question 2

Enthalpy change of formation

Answer 2

Energy absorbed when one mole of pure solid is formed from constituent elements in standard state

Question 3

Electron affinity

Answer 3

Enthalpy change when one mole of gaseous atoms or negatively charged ions gains one mole of electrons

Question 4

Enthalpy change of solution

Answer 4

Enthalpy change when one mole of solvent is completely dissolved in a solvent to form an infinitely dilute solution

Question 5

Enthalpy change of combustion

Answer 5

Energy released when one mole of substance is completely burnt in excess oxygen

Question 6

Enthalpy change of hydration

Answer 6

Energy released when one mole of gaseous ions are dissolved in a large amount of water

Question 7

Enthalpy change of neutralisation

Answer 7

Energy released when one mole of water is formed when an acid neutralises a base in an infinitely dilute aqueous solution

Question 8

Bond energy

Answer 8

Energy absorbed when one mole of covalent bonds between two atoms in a gaseous molecule are broken

Question 9

Ionisation energy

Answer 9

Energy absorbed when one mole of gaseous atoms or ions loses one mole of electrons to form one mole of singly (doubly… so on) positive gaseous ions

Question 10

Lattice energy

Answer 10

Energy released when one mole of ionic solid is formed from its isolated gaseous ions an infinite distance apart

Question 11

Mnemonics

Answer 11

FEaS (both)
CHNLE (-ve)
BAI (+ve)

LEA (isolated) and SLEN (infinite)
Gaseous (everything other than neutralisation, combustion, formation and solution)

Question 12

Enthalpy change of atomisation

Answer 12

Energy absorbed when one mole of isolated gaseous atoms are formed from their elements in standard state

Question 13

Lattice energy

Answer 13

Energy released when one mole of ionic solid is formed from isolated gaseous ions an infinite distance apart.