Unit 1: Chemical Changes and Structure

Question 1

Temperature

Answer 1

Measure of how fast or slow particles move

Question 2

Catalyst

Answer 2

Speeds up the rate of reaction but is not used up in the reaction.

Question 3

Soluble

Answer 3

Can dissolve in water

Question 4

Atomic Number

Answer 4

Equal to the number of protons in an atom

Question 5

Ions

Answer 5

A charged particle

Question 6

Isotopes

Answer 6

Atoms with the same atomic number, but different mass number

Question 7

Relative Atomic Mass

Answer 7

Average mass of isotopes of an element

Question 8

Molecules

Answer 8

Two or more atoms joined together by covalent bonds. A molecule is usually made from non-metals.

Question 9

Covalent Bond

Answer 9

A shared pair of electrons between two non-metal atoms.

Question 10

Diatomic molecules

Answer 10

Molecules made from two atoms

Question 11

Ionic Bond

Answer 11

Electrostatic force of attraction between a positive metal ion and a negative non-metal ion.

Question 12

Lattice

Answer 12

Regular arrangement of positive and negative ions.

Question 13

Molten

Answer 13

Heat up by a Bunsen burner

Question 14

Covalent network

Answer 14

Giant network of strong covalent bonds

Question 15

Covalent molecules

Answer 15

Strong covalent bonds between atoms but only weak intermolecular bonds between molecules.

Question 16

Chemical formula

Answer 16

Gives ratio of atoms or ions in a compound

Question 17

Valency

Answer 17

Number of bonds an atom forms

Question 18

Gram Formula Mass

Answer 18

Mass of one mole

Question 19

Excess

Answer 19

More than enough for reaction to take place

Question 20

Indicator

Answer 20

Chemical that can change colour in the presence of an acid or base

Question 21

pH scale

Answer 21

Measure the Hydrogen ion concentration and tells us how acidic or basic a substance is

Question 22

Base

Answer 22

Any substance that can neutralise an acid

Question 23

Alkali

Answer 23

A soluble base

Question 24

Dissociation

Answer 24

Breaks up

Question 25

Salt

Answer 25

Ionic compound that is formed from the neutralisation of an acid with a base

Question 26

Spectator ions

Answer 26

Remain unchanged by a reaction

Question 27

Standard solution

Answer 27

Solution of accurately known concentration

Question 28

Concordant

Answer 28

Results within 0.2cm3 of each other