AQA GCSE Chemistry 4.8 Chemical analysis overview quiz quiz

A single element or compound not mixed with anything else

Any substance that is clean, natural and safe to drink or use

A useful mixture of two or more different substances

A substance that has no colour and no smell

A pure substance melts over a wide range; an impure one melts at one sharp point

A pure substance has a sharp melting point; an impure one melts over a range

Both pure and impure substances melt at exactly the same fixed temperature

Pure substances do not melt at all when they are heated up

A single pure compound made of only one type of molecule throughout

An element found in its natural state in the ground before any processing has happened

A mixture designed as a useful product with measured quantities of components

A type of chemical reaction that combines several elements together

The solvent

The dissolved mixture

The beaker

The paper

Distance moved by spot divided by distance moved by solvent

Distance moved by solvent divided by distance moved by spot

Distance moved by spot times distance moved by solvent

Distance moved by spot minus distance moved by solvent

$0.3$

$0.6$

$1.67$

$2.0$

It relights a glowing wooden splint

It turns limewater cloudy and milky

A lit splint gives a squeaky pop

It bleaches damp blue litmus paper

It gives a squeaky pop with a lit splint

It relights a glowing wooden splint

It turns damp litmus paper red then white

It turns limewater milky (cloudy)

Yellow

Crimson red

Pale lilac

Blue-green

A cream precipitate

A white precipitate

A yellow precipitate

No change

Silver nitrate

Limewater

Barium chloride

Sodium hydroxide

They are much slower to run but far cheaper to set up

They cannot detect very small amounts of a substance

They use no specialist equipment or trained operators

They are faster, more sensitive and more accurate