Definitions

Question 1

Define Relative atomic mass

Answer 1

Mean mass of an atom relative to 1/12th the mass of an atom of carbon-12

Question 2

Relative Molecular mass

Answer 2

Mean mass of a molecule relative to 1/12th the mass of an atom of carbon-12

Question 3

Relative isotopic mass

Answer 3

The mass of one atom of an isotope relative to 1/12th of the mass of an atom of carbon-12

Question 4

First ionisation energy

Answer 4

Energy required for the removal of one mole of electrons from one mole of atoms to form one mole of gaseous 1+ ions

Question 5

Orbital

Answer 5

A volume of space where there is a high chance of finding an electron. Orbitals contain 2 electrons that spin in opposite directions

Question 6

Ionic bonding

Answer 6

The strong electrostatic attraction between oppositely charged ions

Question 7

Covalent bond

Answer 7

Strong electrostatic attraction between two nuclei and the shared pair of electrons between them

Question 8

Electronegativity

Answer 8

The power of an atom to attract the bonding pair of electrons in a covalent bond

Question 9

Metallic bonding

Answer 9

The strong electrostatic attraction between metal ions and delocalised electrons

Question 10

What is a Dative/Coordinate Bond

Answer 10

Both electrons in a covalent bond come from one atom

Question 11

Define Oxidation number

Answer 11

An oxidation state/number shows the charge on an atom if all of its bonds were considered totally ionic

Question 12

What is disproportionation

Answer 12

An element in a single species is simultaneous oxidised and reduced

Question 13

Define enthalpy change

Answer 13

Enthalpy change is the heat change in a reaction at constant pressure

Question 14

What are standard conditions for pressure and temperature

Answer 14

100 kPa and 298 K

Question 15

Define enthalpy change of reaction

Answer 15

Enthalpy change of a reaction according to the molar quantities in the equation under standard conditions

Question 16

Define enthalpy change of formation

Answer 16

Enthalpy change when one mole of substance is formed from elements in their standard states under standard conditions

Question 17

Define enthalpy change of combustion

Answer 17

Enthalpy change when one mole of substance completely combusts in oxygen to form CO2 and H2O under standard conditions

Question 18

Define enthalpy change of neutralisation

Answer 18

The enthalpy change when and acid and alkali react to form 1 mole of water under standard conditions

Question 19

Define bond enthalpy

Answer 19

Energy required to break one mole of a bond type in a molecule in the gaseous state

Question 20

Define dynamic equilibrium

Answer 20

Rate of forwards and backwards reaction is the same. Concentration of reactants and products are constant

Question 21

Define lattice enthalpy of formation

Answer 21

Enthalpy change when 1 mole of a solid ionic compound is formed from its gaseous ions under standard conditions

Question 22

Define enthalpy change of atomisation with an example equation for Fluorine

Answer 22

The enthalpy change when 1 mole of gaseous atoms is made from an element in its standard state
1/2 F2 (g) —-> F(g)

Question 23

Define first electron affinity

Answer 23

The enthalpy change when 1 mole of gaseous 1- ions are made from 1 mole of gaseous atoms.

Question 24

Define 2nd electron affinity

Answer 24

The enthalpy change when 1 mole of gaseous 2- ions are made from 1 mole of gaseous 1- ions