Definitions

Question 1

Relative isotopic mass

Answer 1

mass of an atom of isotope relative to 1/12 of the mass of an atom of 12C.

Question 2

Relative atomic mass

Answer 2

average mass of an atom of an element relative to 1/12 of the mass of an atom of 12C

Question 3

Relative molecular mass

Answer 3

average mass of one molecule of a substance relative to 1/12 of the mass of an atom of 12C

Question 4

Relative formula mass

Answer 4

mass of one formula unit of a substance relative to 1/12 of the mass of one atom of 12C

Question 5

Mole

Answer 5

one mole is the amount of substance that contains 6.02x10^23 particles

Question 6

Disproportionation reaction

Answer 6

redox reaction in which one species is simultaneously oxidized and reduced

Question 7

Mass number/nucleon number

Answer 7

total number of protons and neutrons in an atom

Question 8

Proton number

Answer 8

Number of protons in the nucleus of an atom

Question 9

Isotopes

Answer 9

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

Question 10

First ionization energy

Answer 10

The energy absorbed to remove one mole of electrons from one mole of gaseous atoms to form one mole of singly charged positive gaseous ions.

Question 11

Electronegativity

Answer 11

measure of the ability of an atom in a molecule to attract the shared pair of electrons in a covalent bond.

Question 12

Ionic bond

Answer 12

strong electrostatic attraction between oppositely charged ions formed by the transfer of electrons between the original atoms

Question 13

Covalent bond

Answer 13

strong electrostatic attraction between the positive nuclei of the two atoms and the bonding electrons shared between them.

Question 14

Dative/co-ordinate bond

Answer 14

covalent bond in which both electrons come from the same atom

Question 15

Metallic bond

Answer 15

strong electrostatic forces of attraction between metal cations and mobile sea of delocalized electrons.

Question 16

Bond energy

Answer 16

Energy is absorbed when one mole of a given covalent bond in a gaseous compound is broken into gaseous atoms or molecules

Question 17

Lattice energy

Answer 17

Energy released when one mole of ionic solid is formed from its constituent gaseous ions.

Question 18

Hess’ Law

Answer 18

Enthalpy change for a reaction is the same whether the reaction takes place in one step or in a series of steps and is determined by the initial and final states of the system.

Question 19

Standard Enthalpy Change of Formation

Answer 19

The energy change when one mole of substance is formed from its constituent elements in their standard states at 298 K and 1 bar.

Question 20

Standard Enthalpy Change of Combustion

Answer 20

The energy evolved when one mole of substance is burnt completely in excess oxygen at 298 K and 1 bar.

Question 21

Standard Enthalpy Change of neutralisation

Answer 21

The energy evolved when one mole of water is formed in the reaction between an acid and a base at 298 K and 1 bar.

Question 22

Rate equation

Answer 22

mathematical relationship between the reaction rate and the
concentration of the individual reactants.

Question 23

Rate constant

Answer 23

proportionality constant for a given reaction at a certain temperature

Question 24

Order of reaction

Answer 24

power to which that reactant’s concentration is raised to in an experimentally determined rate reaction

Question 25

Overall order of reaction

Answer 25

sum of the individual orders of reaction with respect to all the reactants

Question 26

Dynamic equillibrium

Answer 26

reversible process at equilibrium in which the rate of the forward reaction equals to the rate of backward reaction, with the concentrations of reactants and products remaining constant over time.

Question 27

Buffer solution

Answer 27

a solution containing a weak acid and its conjugate base or a weak base and its conjugate acid which resists and does not show significant changes in pH when small amount of strong acid or strong base are added to it.

Question 28

Constitutional isomer

Answer 28

Compounds with same molecular formula but different structural formula

Question 29

Stereoisomerism

Answer 29

compounds have the same molecular formula and the same structural formula, but the atoms in the molecules have different spatial arrangements.

Question 30

Cis-trans isomerism

Answer 30

Restricted rotation about the Carbon double bond The 2 groups bonded to each carbon in the C=C bond must not be identical.

Question 31

Polymer

Answer 31

macromolecule built up from monomers, with average molar mass of at least 1000 or at least 100 repeat units.

Question 32

Nanomaterial

Answer 32

Material with at least one dimension on the nanoscale (1-100nm)

Question 33

Nanoparticle

Answer 33

Material with all three dimensions on the nanoscale (1-100nm)