C4 - Chemical Changes

What is oxidation?

Gain of oxygen or loss of electrons.

What is reduction?

Loss of oxygen or gain of electrons.

What is a redox reaction?

A reaction where both oxidation and reduction occur.

What is an electrolyte?

An ionic compound that conducts electricity when molten or dissolved.

What are ions attracted to at the electrodes?

Positive ions → cathode (gain electrons); negative ions → anode (lose electrons).

What is the reactivity series (top to bottom)?

Potassium, Sodium, Calcium, Magnesium, Aluminium, Carbon, Zinc, Iron, Hydrogen, Copper

What happens when metals react with acids?

Metal + Acid → Salt + Hydrogen.

What is a neutralisation reaction?

Acid + Base → Salt + Water

What ions are responsible for acidity and alkalinity?

Acids = H⁺ ions; Alkalis = OH⁻ ions.

What is electrolysis used for?

To extract metals and split compounds using electricity.

What forms at the cathode during electrolysis of molten compounds?

The metal.

What forms at the anode?

The non-metal (gas).