Year 1

Question 1

Isotope

Answer 1

Atoms of the same element with the same number of protons but different numbers of neutrons.

Question 2

Relative atomic mass

Answer 2

Average mass of an atom relative to 1/12th of the mass of a carbon-12 atom.

Question 3

Relative isotopic mass

Answer 3

Average mass of an isotope relative to 1/12th of the mass of a carbon-12 atom.

Question 4

Orbital

Answer 4

Region around the nucleus that can hold up to 2 electrons with opposite spins.

Question 5

Ionisation Energy

Answer 5

Energy change when one mole of electrons is removed from one mole of isolated gaseous atoms.

Question 6

Acid

Answer 6

Proton donor (H+ donor).

Question 7

Base

Answer 7

Proton acceptor (H* acceptor).

Question 8

Salt

Answer 8

Made when H* of an acid is replaced by a metal ion or NH4*.

Question 9

Oxidation

Answer 9

Loss of electrons or increase in oxidation number.

Question 10

Reduction

Answer 10

Gain of electrons or decrease in oxidation number.

Question 11

Disproportionation

Answer 11

Reaction where an element is simultaneously oxidised and reduced.

Question 12

Amount of substance

Answer 12

The number of moles of substance.

Question 13

Mole

Answer 13

Amount of substance containing 6.02 x 10^23 particles.

Question 14

Avogadro constant, NA

Answer 14

Number of particles present in a mole (6.02 x 10^23).

Question 15

Ionic bond

Answer 15

Electrostatic attraction between positive ions and negative ions.

Question 16

Covalent bond

Answer 16

Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.

Question 17

Coordinate bond (Dative Covalent Bond)

Answer 17

Shared pair of electrons with one atom contributing both electrons.

Question 18

Metallic bond

Answer 18

Electrostatic attraction between positive ions and delocalised electrons.

Question 19

Electronegativity

Answer 19

Power of an atom to attract the bonding electrons in a covalent bond.

Question 20

What is periodicity in the context of the Periodic Table?

Answer 20

Repeated patterns across periods of the Periodic Table.

Question 21

What is the enthalpy of reaction?

Answer 21

Enthalpy change when one mole of reactants reacts in a specified chemical equation.

Question 22

What is the standard enthalpy of formation?

Answer 22

Enthalpy change when one mole of compound forms from its elements in their standard states under standard conditions.

Question 23

What is the standard enthalpy of combustion?

Answer 23

Enthalpy change when one mole of compound undergoes complete combustion in oxygen under standard conditions.

Question 24

What is the standard enthalpy of neutralisation?

Answer 24

Energy change when one mole of water forms when an aqueous acid neutralises an aqueous base under standard conditions.

Question 25

What are the standard conditions for measuring enthalpy changes?

Answer 25

100 KPa and 298 K.

Question 26

What is bond enthalpy?

Answer 26

Energy needed to break 1 mole of covalent bonds in a substance in the gaseous state.

Question 27

What is activation energy (Ea)?

Answer 27

Minimum energy a particle must have for a reaction to occur.

Question 28

What is a homogeneous catalyst?

Answer 28

Catalyst in the same state as the reactants.

Question 29

What is a heterogeneous catalyst?

Answer 29

Catalyst in a different state from the reactants.

Question 30

What is dynamic equilibrium?

Answer 30

Rate of forward and reverse reactions are equal and concentration of reactants and products are constant.

Question 31

What is a hydrocarbon?

Answer 31

Molecule containing hydrogen and carbon atoms only.

Question 32

What is a homologous series?

Answer 32

Series of organic compounds with the same general molecular formula, same functional group, successive formulae differ by CH2.

Question 33

What is a stereoisomer?

Answer 33

Molecules with the same structural formula but different arrangement of atoms in space.

Question 34

What is E/Z isomerism?

Answer 34

Type of stereoisomerism where each carbon in C=C is bonded to two different groups.

Question 35

What is homolytic fission?

Answer 35

Breaking of a covalent bond where both atoms take one of the shared pair of electrons.

Question 36

What is heterolytic fission?

Answer 36

Breaking of a covalent bond where one atom takes the shared pair of the electrons.

Question 37

What is a radical?

Answer 37

Species with an unpaired electron.

Question 38

What is the bond type for a sigma (σ) bond?

Answer 38

Direct overlap of orbitals between the bonding atoms.

Question 39

What is the bond type for a pi (π) bond?

Answer 39

Sideways overlap of two adjacent p orbitals.

Question 40

What is an electrophile?

Answer 40

Electron pair acceptor.

Question 41

What is a nucleophile?

Answer 41

Electron pair donor.