Chemical Changes

Question 1

Chemical

Answer 1

Chemical changes occur when a substance combines with another to form a new substance.

Question 2

Physical

Answer 2

Physical changes are changes affecting the form of a chemical substance, but not its chemical composition.

Question 3

Physical Properties

Answer 3

Properties that you can either observe using your five senses — seeing, hearing, touching, smelling and tasting — or measure directly

Question 4

Chemical Properties

Answer 4

Properties that describe how a substance combines with other substances to form new chemicals or how a substance breaks up into two or more different substances

Question 5

Flammability

Answer 5

An indicator of how easily a substance catches fire

Question 6

Reactivity

Answer 6

A measure of how likely a particular metal is to take part in a displacement reaction

Question 7

Toxicity

Answer 7

The danger to your health caused when poisonous substances combine with chemicals in your body to produce new substances and damaging effects

Question 8

Sublimation

Answer 8

Sublimation is a chemical process where a solid turns into a gas without going through a liquid stage.

Question 9

Melting

Answer 9

Make or become liquefied by heating.

Question 10

evaporation

Answer 10

The process of turning from liquid into vapour or gas.

Question 11

Solid

Answer 11

Firm and stable in shape; not liquid or fluid.

Question 12

Solidification

Answer 12

Solidification, also known as freezing, is a phase change of matter that results in the production of a solid. This occurs when the temperature of a liquid is lowered below its freezing point.

Question 13

Liquid

Answer 13

A substance that flows freely but is of constant volume

Question 14

Condensation

Answer 14

The conversion of a vapour or gas to a liquid.

Question 15

Gas

Answer 15

An air-like fluid substance which expands freely to fill any space available, irrespective of its quantity.

Question 16

Deposition

Answer 16

Desublimation or deposition is the phase change from gas directly to solid, with no intermediate liquid phase. Desublimation is the reverse process of sublimation.

Question 17

Chemical Reaction

Answer 17

A chemical change in which one or more new chemical substances are produced

Question 18

Reactants

Answer 18

Chemical substance used up in a chemical reaction. Some chemical bonds in a reactant are broken during the reaction.

Question 19

Products

Answer 19

New chemical substance that results from a chemical reaction

Question 20

Precipitate

Answer 20

Solid product of a chemical reaction that does not dissolve in water

Question 21

Reaction Rate

Answer 21

Speed at which a reaction takes place

Question 22

Catalyst

Answer 22

Chemical that helps to start or speed up a chemical reaction

Question 23

Rusting

Answer 23

The corrosion of iron

Question 24

Corrosion

Answer 24

A chemical reaction that wears away a metal. Air, water or chemicals in air and water, as well as many household substances, can be corrosive.

Question 25

Rust

Answer 25

A brown substance formed when iron reacts with oxygen and water

Question 26

Surface Protection

Answer 26

Coating over a metal surface to prevent corrosion

Question 27

Galvanising

Answer 27

Protecting a metal by covering it with a more reactive metal that will corrode first

Question 28

Burning

Answer 28

Combining a substance with oxygen in a flame

Question 29

Oxidation

Answer 29

Chemical reaction involving the loss of electrons by a substance

Question 30

Fossil Fuel

Answer 30

Substance, such as coal, oil and natural gas, that has formed from the remains of ancient organisms.

Question 31

Combustion

Answer 31

The process of combining with oxygen, most commonly burning with a flame