Year 8 End of Year Chemistry Exam Revision

Exothermic

A reaction in which heat energy is given out to the surroundings

Endothermic

A reaction in which heat energy is taken in from the surroundings

Complete combustion

When a fuel is burnt in a plentiful supply of oxygen

Incomplete combustion

When a fuel is burnt in a limited supply of oxygen

Chemical Change

A change which involves the formation of one or more new substances.

Physical Change

A change where no new substances are made, but there is a change in the appearance of a chemical

Metal + Acid -->

Salt + Hydrogen

Base + Acid -->

Salt + Water

Metal + Water -->

Metal hydroxide + Hydrogen

Products of complete combustion

Carbon dioxide + Water

Products of incomplete combustion

Carbon monoxide + Particulates + Water

Igneous rock

Formed when magma (molten rock) cools and solidifies

Metamorphic rock

Formed from other rocks that are changed because of heat or pressure

Sedimentary rock

Formed by the compaction and cementation of sediments over millions of years

An example of an igneous rock

Graphite

An example of an metamorphic rock

Marble

An example of an sedimentary rock

Limestone

Weathering

Rocks gradually wearing away due to physical, chemical and biological processes

Acid rain

When sulphur dioxide (from combustion) dissolves in rainwater making it acidic

Fossil Fuels

Coal, oil, natural gas

Crust

Thin and brittle rock

Mantle

Solid rock which can flow very slowly

Inner core

Solid nickel and iron

Outer core

Molten nickel and iron

Composition of atmosphere

78% Nitrogen, 20% Oxygen, 0.04% Carbon dioxide, 1.96% Other gases

Conservation of mass

No material is lost or gained in either a chemical or physical change

Metal carbonate + Acid -->

Salt + Water + Carbon dioxide

Evaporation

Liquid to gas

Melting

Solid to liquid

Condensation

Gas to liquid

Freezing

Liquid to solid

Where metals are found on the periodic table

Left

Where non-metals are found on the periodic table

Right

Fossil

The remains or impression of a prehistoric plant or animal embedded and preserved in rock

How to make an investigation a 'Fair Test'

Keep the control variable the same

How to make an investigation 'Reliable'

Repeat experiment and calculate a mean excluding anomalies

Compound

Two or more elements chemically combined together

Element

A substance containing only one type of atom

Mixture

Two or more elements physically combined together