Definitions

Question 1

Rate determining step

Answer 1

The slowest step in a reaction

Question 2

Heterogeneous equilibrium

Answer 2

An equilibrium reaction that involves substances in different phases

Question 3

Homogeneous equilibrium

Answer 3

An equilibrium reaction that involves substances in the same phase

Question 4

Bronstead-Lowry acid

Answer 4

A proton donor

Question 5

Bronstead-Lowry base

Answer 5

A proton acceptor

Question 6

Catalyst

Answer 6

A substance which speeds up the rate of reaction without being used up

Question 7

Buffer solution

Answer 7

A system that minimises pH change on the addition of small amounts of acid or base

Question 8

Conjugate acid-base pair

Answer 8

A pair of compounds that transform into each other by the transfer of a proton

Question 9

Dibasic acid

Answer 9

An acid that can donate 2 moles of H ions per 1 mole of acid

Question 10

End point

Answer 10

The point in a titration where the indicator changes colour (a suitable indicator should change near the equivalence point)

Question 11

Equivalence point

Answer 11

The point in a titration when the amount of acid is exactly equal to the amount of base

Question 12

Indicator

Answer 12

A weak acid tbat changes colour based on an equilibrium shift between [HA] and [A-]

Question 13

Equivalence point

Answer 13

The point in a titration when the amount of acid is exactly equal to the amount of base

Question 15

Monobasic acid

Answer 15

An acid which donates 1 mole of H ions per 1 mole of acid

Question 16

Enthalpy

Answer 16

A value that represents the heat content of a system

Question 17

Enthalpy change

Answer 17

The change in the heat content of a system during a reaction

Question 18

Enthalpy

Answer 18

A value that represents the heat content of a system

Question 19

Enthalpy change if atomisation

Answer 19

The enthalpy change that takes place when one mole of gaseous atoms is formed from an element in its standard state

Question 20

Enthalpy change of formation

Answer 20

The enthalpy change that takes place when one mole of a compound is formed from its elements

Question 21

Enthalpy change of hydration

Answer 21

The enthalpy change that takes place when one mole of gaseous ions is dissolved in water to form one mole of aq ions (increased ionic charge and decreased radii make this more negative as there would be greater attraction between the water molecules and ions

Question 22

Enthalpy change of solution

Answer 22

The enthalpy change that takes place when one mole of solute is dissolved

Question 23

First electron affinity

Answer 23

The amount of energy released when one mole of electrons is added to one mole of gaseous atoms, forming one mole of gaseous 1- ions

Question 24

First ionisation energy

Answer 24

The removal of one mole of electrons from one mole of gaseous atoms, to form one mole of gaseous 1+ ions

Question 25

Lattice enthalpy

Answer 25

The formation of one mole of an ionic lattice from gaseous ions

Question 26

Entropy

Answer 26

A measure of the disorder within a system. (The greater the entropy, the more disordered a system)

Question 27

Disproportionation

Answer 27

A reaction where the same element is oxidised and reduced

Question 28

Relative atomic mass

Answer 28

The weighted mean mass of an atom compared with 1/12 of the mass of carbon 12

Question 30

Redox reaction

Answer 30

A reaction that involves both oxidation and reduction

Question 31

Oxidising agent

Answer 31

A reagent which oxidises another species, an electron acceptor

Question 32

Reducing agent

Answer 32

A reagent which reduces another species, an electron donor

Question 33

Atomic orbital

Answer 33

A region of space around the nucleus of an atom which holds up to two electrons with opposite spins

Question 34

Sub shell

Answer 34

A group of the same type of atomic orbital

Question 35

Dative covalent bond/coordinate bond

Answer 35

A shared pair of electrons which has been provided by one atom only

Question 36

Electronegativity

Answer 36

A measure of the ability of an atom to attract the pair of electrons in a covalent bond

Question 37

Hydrogen bond

Answer 37

A strong dipole-dipole interaction between an electron deficient hydrogen atom on one molecule and a lone pair on the O,N, or F on a different molecule

Question 38

Lone pair

Answer 38

An outer shell pair of electrons that isn’t involved in bonding

Question 39

Periodicity

Answer 39

The regular repeating pattern of properties of the elements across the periodic table

Question 40

Activation energy

Answer 40

The minimum energy required for a reaction to occur

Question 41

Enthalpy change of neutralisation

Answer 41

The enthalpy change that takes place when an aqueous acid and an aqueous alkali react to produce one mole of water

Question 42

Closed system

Answer 42

A system which allows the transfer of energy but not matter

Question 43

Dynamic equilibrium

Answer 43

A continuous reaction which exists in a closed system where the rate of the forward reaction is equal to the rate of the reverse reaction

Question 45

Aliphatic

Answer 45

An organic compound that consists of straight or branched chains

Question 46

Alicyclic

Answer 46

An aliphatic compound arranged in non aromatic rings

Question 47

Aromatic

Answer 47

A compound containing at least one benzene ring

Question 48

Alkyl group

Answer 48

A group with the general formula Cn H2n+1