Thermodynamics year 2

Question 1

Enthalpy change of formation

Answer 1

The standard enthalpy change of formation of a compound is 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 of atomisation of an element is 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 bond dissociation enthalpy is the standard molar enthalpy change when one mole of a covalent bond is broken into two gaseous atoms (or free radicals)

Question 4

First Ionisation enthalpy

Answer 4

The first ionisation enthalpy is the enthalpy change
required to remove 1 mole of electrons from 1 mole of
gaseous atoms to form 1 mole of gaseous ions with a +1
charge

Question 5

Second Ionisation enthalpy

Answer 5

The second ionisation enthalpy is the enthalpy change to remove 1 mole of electrons from one mole of gaseous 1+ ions to produces one mole of gaseous 2+ ions.

Question 6

Enthalpy of hydration

Answer 6

The standard enthalpy change when water molecules surround one mole of gaseous ions.

Question 7

Lattice enthalpy of dissociation

Answer 7

Standard enthalpy change when one mole of solid ionic compound dissociates into its gaseous ions

Question 8

Enthalpy of solution

Answer 8

Standard enthalpy change when one mole of solute dissolves completely in sufficient solvent to form a solution in which the molecules or ions are far apart not to interact with each other.