Definitions

Question 1

Enthalpy change of formation

Answer 1

Energy transferred when one mole of a compound is formed from its elements under standard conditions, all reactants and products being in their standard states

Question 2

Enthalpy of atomisation

Answer 2

Enthalpy change when one mole of gaseous atoms is formed from the element in its standard state

Question 3

First ionisation enthalpy

Answer 3

Enthalpy change required to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous ions with a 1+ charge

Question 4

Second ionisation enthalpy

Answer 4

And Sophie change required to remove one mole of electrons from one mole of gaseous 1+ ions to produce one mole of gaseous 2+ ions

Question 5

First electron affinity

Answer 5

Enthalpy change that occurs when one mole of gaseous atoms gain is one mole of electrons to form one mole of gaseous ions with a 1- charge

First electron affinity is exothermic for atoms that normally gain electrons to form negative ions, because the ion is more stable than the atom and there is an attraction between the nucleus and the electron

Question 6

Second electron affinity

Answer 6

Enthalpy change when one mole of gaseous 1- ions gain one electron per ion to produce gases 2- ions

Second electron affinity for oxygen is endothermic because it takes in energy to overcome the proportional force between the negative ion and the electron

Question 7

Enthalpy change of hydration

Answer 7

Enthalpy change when one mole of gaseous ions dissolved in water

Question 8

Enthalpy change of solution

Answer 8

Enthalpy change when one mole of solute dissolves in water