Module 3 - Keywords

Question 1

Periodicity

Answer 1

Repeating trends in physical and chemical properties across periods

Question 2

s block element

Answer 2

An element with its highest energy electron in an s orbital

Question 3

p block element

Answer 3

An element with its highest energy electron in a p orbital

Question 4

d block element

Answer 4

An element with its highest energy electron in a d orbital

Question 5

First ionisation energy

Answer 5

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

Question 6

Second ionisation energy

Answer 6

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

Question 7

Successive ionisation energies

Answer 7

Energy required to remove each subsequent 1 mole of electrons from 1 mole of gaseous ions

Question 8

Nuclear charge

Answer 8

The positive charge found on the nucleus of every atom

Question 9

Metallic bonding

Answer 9

Strong electrostatic attraction between cations (positive ions) and delocalised electrons

Question 10

Giant covalent lattices

Answer 10

Networks of atoms bonded by strong covalent bonds

Question 11

Diatomic

Answer 11

Molecule containing 2 atoms

Question 12

Disproportionation

Answer 12

Oxidation and reduction of the same element

Question 13

Bleach

Answer 13

Formed by the reaction of chlorine with cold, dilute aqueous sodium hydroxide

Question 14

Precipitate

Answer 14

A solid that forms on reaction of solutions

Question 15

Halide

Answer 15

A compound containing an element from group 17 (halogens)

Question 16

Exothermic

Answer 16

Reaction which releases energy. ΔH is negative. Bond making

Question 17

Endothermic

Answer 17

Reaction which takes in energy. ΔH is positive. Bond breaking

Question 18

Activation energy

Answer 18

The minimum energy which must be available to a chemical system with potential reactants to result in a chemical reaction

Question 19

Standard conditions

Answer 19

100kPa, 298K, substances in their standard states

Question 20

Enthalpy change of reaction, Δ_rH

Answer 20

Enthalpy change associated with a stated equation

Question 21

Enthalpy change of formation, Δ_fH

Answer 21

Enthalpy change associated with the formation of 1 mole of a compound from its elements

Question 22

Enthalpy change of combustion, Δ_cH

Answer 22

The enthalpy change associated with the complete combustion of 1 mole of a compound

Question 23

Enthalpy change of neutralisation, Δ_nH

Answer 23

The enthalpy change associated with the formation of 1 mole of water in a neutralisation reaction

Question 24

Average bond enthalpy

Answer 24

A measurement of covalent bond strength. It’s the energy change associated with breaking 1 mole of bonds in gaseous molecules

Question 25

Hess’s law

Answer 25

The total energy change for a reaction is the same regardless of the route taken

Question 26

Concentration

Answer 26

A measure of the number of a type of particle in a certain volume (gdm^-3 or moldm^-3)

Question 27

Simple collision theory

Answer 27

In order to react, particles need to collide and have the activation energy needed to react

Question 28

Rate of reaction

Answer 28

The change in concentration of a reactant or a product with time

Question 29

Catalyst

Answer 29

A chemical that provides a new route for the reaction with a lower activation energy. It is not used up in a chemical reaction.

Question 30

Homogeneous

Answer 30

A catalyst in the same phase as the reagents

Question 31

Heterogeneous catalyst

Answer 31

A catalyst in a different phase to the reagents

Question 32

Boltzmann distribution

Answer 32

A graph that shows the probability distribution of particles with different energies

Question 33

Dynamic equilibrium

Answer 33

An equilibrium where the rate of the forward reaction is equal to the rate of the reverse reaction

Question 34

Closed system

Answer 34

A reaction where nothing can enter or leave the container

Question 35

Equilibrium constant, K_c

Answer 35

A measure of the position of a dynamic equilibrium which relates the concentrations of the reactants and products