Edexcel GCSE Combined Science CC3 and CC4 Chemical changes and extracting metals overview quiz quiz

Hydroxide ions

Sodium ions

Hydrogen ions

Chloride ions

A salt and hydrogen gas given off as bubbles

A salt and water only

A salt and oxygen

A salt, water and carbon dioxide

H+ + OH- gives H2O

H+ + Cl- gives HCl

Na+ + Cl- gives NaCl

O2 + H2 gives H2O

To make the reaction run much faster and produce its salt far more quickly

To make sure all the acid reacts, leaving none in the crystals

To change the colour of the final salt crystals

To lower the pH of the solution still further

The anode, which is the positive electrode

Both electrodes equally

The cathode (negative electrode)

Neither electrode

Lead

Hydrogen

Oxygen

Bromine

Loss of electrons

Gain of electrons

Gain of protons

Loss of neutrons

The less reactive metal

The more reactive metal

The heavier metal

Neither, they do not react

By electrolysis of the molten iron oxide ore

By adding water to the iron oxide and stirring

By heating with carbon, which removes the oxygen

It is found native as the pure metal and needs no extraction at all

Electrolysis is always far cheaper than heating the ore with carbon in a furnace

Aluminium is found as the pure native metal

Carbon reacts violently with aluminium metal

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

So the ions are free to move and carry charge

To make the ionic compound much lighter than before

To change the solid ionic compound into a gas first

So that it can conduct electricity while still a solid

Magnesium chloride

Magnesium sulfate

Magnesium nitrate

Magnesium carbonate