AQA GCSE Chemistry 4.4 Chemical changes overview quiz quiz

The loss of electrons

The gain of electrons

The gain of protons

The loss of neutrons

A salt and water

A salt and hydrogen

A salt, water and carbon dioxide

An oxide and hydrogen

Silver

Gold

Iron

Copper

Aluminium is less reactive than carbon, so carbon cannot displace it from its ore

Aluminium forms no stable oxide, so there is nothing for carbon to reduce at all

Carbon is far too expensive to use as a reducing agent on an industrial scale

Aluminium is more reactive than carbon, so carbon cannot remove its oxygen

Hydrogen ions, $H^+$

Hydroxide ions, $OH^-$

Sodium ions, $Na^+$

Oxide ions, $O^{2-}$

$H^+ + Cl^- \rightarrow HCl$

$H^+ + OH^- \rightarrow H_2O$

$Na^+ + OH^- \rightarrow NaOH$

$H_2 + O_2 \rightarrow H_2O$

A salt and hydrogen gas, with no water produced

A salt and water only, with no gas given off at all

A salt, water and carbon dioxide

A metal oxide and carbon dioxide gas only

A strong acid is always concentrated while a weak acid is always very dilute in water

A strong acid has a higher pH than a weak acid of the same concentration in water

There is no real chemical difference between a strong acid and a weak acid

A strong acid is fully ionised in water and a weak acid is only partly ionised

They are reduced by gaining electrons

They are oxidised by losing electrons

They move to the anode

They form a gas at the anode

Sodium

Chlorine

Hydrogen

Oxygen

To increase the melting point so the mixture stays solid for longer

To act as the cathode where the aluminium metal is produced

To lower the melting point of aluminium oxide and save energy

To remove impurities of carbon from the molten electrolyte

Sodium sulfate

Sodium nitrate

Sodium carbonate

Sodium chloride