Thermodynamics

Question 1

Enthalpy change of formation

Answer 1

the energy transferred when 1 mole of the compound is formed from its elements under standard conditions (298K and 100kpa), all reactants and products being in their standard states

Question 2

Enthalpy of atomisation

Answer 2

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

Question 3

Bond dissociation enthalpy

Answer 3

the standard molar enthalpy change when one mole of a covalent bond is broken into two gaseous atoms

Question 4

First electron affinity

Answer 4

the enthalpy change that occurs when 1 mole of gaseous atoms gain 1 mole of electrons to form 1 mole of gaseous ions with a –1 charge

Question 5

Second electron affinity

Answer 5

the enthalpy change when one mole of gaseous 1- ions gains one electron per ion to produce gaseous 2- ions.

Question 6

Enthalpy of lattice formation

Answer 6

the standard enthalpy change when 1 mole of an ionic crystal lattice is formed from its constituent ions in gaseous form.

Question 7

Enthalpy of lattice dissociation

Answer 7

he standard enthalpy change when 1 mole of an ionic crystal lattice form is separated into its constituent ions in gaseous form.

Question 8

Enthalpy of hydration

Answer 8

Enthalpy change when one mole of gaseous ions become aqueous ions

Question 9

Enthalpy of solution

Answer 9

the standard enthalpy change when one mole of an ionic solid dissolves in a large enough amount of water to ensure that the dissolved ions are well separated and do not interact with one another

Question 10

Trends in Lattice Enthalpies

Answer 10

• size

- charge