KEY DEFINITIONS

Question 1

Relative atomic mass

Answer 1

• The weighted average mass of an atom of an element
• taking into account the natrually occuring isotopes
• relative to 1/12 of the mass of an atom of carbon 12

Question 2

First ionisation energy

Answer 2

• The energy required to remove one electron from each atom
• In one mole of gaseous atoms of an element
• to produce one mole of gaseous 1+ ion

Question 3

Enthalpy change

Answer 3

The measure of heat change in a chemical system

Question 4

Enthalpy change of a reaction

Answer 4

• enthalpy change which accompanies a reaction in the molar quantities shown in a chemical equation
• with all reactants and products in standard states

Question 5

Enthalpy change of formation

Answer 5

• Enthalpy change that takes place when one mole of a compound is formed from its elements
• Under standard conditions with all reactants and products in their standard states

Question 6

Enthalpy change of combustion

Answer 6

• enthalpy change that takes place when one mole of a compound is formed
• under standard conditions with all reactants and products are in standard states

Question 7

enthalpy change of neutralisation

Answer 7

• The energy change which accompanies the reaction of an acid by a base to form one mole of water
• Under standard conditions with all reactants and products under standard states

Question 8

Lattice enthalpy change

Answer 8

*The enthalpy change that accompanies the formation of one mole of an ionic compound
*From its gaseous ions under standard conditions.

Question 9

Standard enthalpy change of atomisation

Answer 9

*The enthalpy change that takes place for the formation of one mole of gaseous atoms.
*In its standard state under standard conditions

Question 10

First electron affinity

Answer 10

*The enthalpy change that takes place when one electron is added to each atom
*of gaseous atoms to form one mol of gaseous 1- ions

Question 11

Standard enthalpy change of solution

Answer 11

*The enthalpy change that takes place when one mole of solute dissolves in a solvent
*The ions from the ionic lattice finish up surrounded with water molecules as aqueous ions

Question 13

Enthalpy change of hydration

Answer 13

*Is the enthalpy change that accompanies the dissolving of gaseous ions in water to form one mole of aqueous ions.