Definitions

Question 1

Isotopes

Answer 1

Atoms of the same element that have a different number of neutrons

Question 2

Relative isotopic mass

Answer 2

Mass of an atom of an isotope compared to 1/12 the mass of an atom of carbon-12

Question 3

Relative atomic mass

Answer 3

Weighted mean mass of an atom compared to 1/12 the mass of an atom of carbon-12

Question 4

Mole

Answer 4

Amount of any substance that has the same number of particles as exactly 12g of carbon-12

Question 5

Molar mass

Answer 5

Mass of 1 mol of substance

Question 6

Salt

Answer 6

Chemical compound formed when the H ion of an acid is replaced with a metal or ammonium ion

Question 7

Hydrated

Answer 7

Contains waters of crystallisation

Question 8

Water of crystallisation

Answer 8

Water molecules in an ionic lattice

Question 9

Acid

Answer 9

Proton donor

Question 10

Base

Answer 10

Proton acceptor

Question 11

Alkali

Answer 11

Soluable base

Question 12

Disproportionation

Answer 12

A reaction where the same element both oxidises and reduces

Question 13

1st Ionisation energy

Answer 13

Energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of +1 gaseous ions

Question 14

Orbital

Answer 14

A region of space which can take a max of 2 electrons with paired opposing spins

Question 15

Isoelectric

Answer 15

Same electron arrangement but different elements

Question 16

Covalent bonding

Answer 16

The electrostatic attract between the positive nuclei of one atom and a pair of shared electrons

Question 17

Dative covalent bond

Answer 17

When one atom supplies both electrons for the bond

Question 18

Ionic bonding

Answer 18

The electrostatic attraction between oppositely charged ions

Question 19

Electronegativity

Answer 19

The ability of an element to attract a pair of electrons from a bond

Question 20

Periodicity

Answer 20

A property that has a pattern across a period that is repeated across successive periods

Question 21

Giant structure

Answer 21

Has no fixed size so can continuously add atoms to the same structure

Question 22

Average bond enthalpy

Answer 22

Energy required to break one mole of bonds in a gaseous molecule

Question 23

Standard enthalpy change of formation

Answer 23

The enthalpy change when one mole of a compound is made from its elements in their standard state under standard conditions (1 atm and 25 degrees)

Question 24

Standard enthalpy change of combustions

Answer 24

Enthalpy change when one mole of substance undergoes complete combustion under standard conditions

Question 25

Standard enthalpy change for neutralisation

Answer 25

Enthalpy change on the formation of one mole of water from the neutralisation of acid with an alkali under standard conditions

Question 26

Hesse’s law

Answer 26

States that an enthalpy change for a reaction is independant of the route taken (providing the initial and final condition are the same)

Question 27

Heterogenous catalyst

Answer 27

A catalyst that is in a different phase (physical state) to the reactants

Question 28

Homogenous catalyst

Answer 28

Same phase as reactants

Question 29

Dynamic equilibrium

Answer 29

A reversible reaction where the rate of the forward reaction is equal to the rate of the backward reaction

Question 30

Structural isomers

Answer 30

Same molecular formule but different structural formula

Question 31

Aliphatic

Answer 31

Straight chains only

Question 32

Homologous series

Answer 32

Compounds with the same functional group and general formula but successive members differ by CH2

Question 33

Functional group

Answer 33

An atom or group of atoms in a compound that determine the characteristic reactions of the molece

Question 34

Radical

Answer 34

An atom of group of atoms with an unpaired electron

Question 35

Homolytic fission

Answer 35

Each bonding atom receives one electron from the bonding pair forming two radicals

Question 36

Isomer

Answer 36

Compounds with the same molecular formula but different chemical structures

Question 37

Stereoisomers

Answer 37

Same structural formula but a different arrangement in space

Question 38

Electrophile

Answer 38

An electron pair acceptor

Question 39

Makownikoff’s rule

Answer 39

The carbocation with the most alkyl groups on the C with the + sign will form as it will be the most stable

Question 40

Nucleophile:

Answer 40

An electron pair donor

Question 41

Volatility

Answer 41

Indicates how easily a liquid will change into a gas

Question 42

Le Chatelier’s principle

Answer 42

The position of equilibrium will shift so as to minimise the effect of any change in condition