Chemical Changes including electrolysis

Define an acid

A substance that forms aqueous solutions with a PH less than 7 and Ionises in water

Define a strong acid and name 3

An acid where all acid particles dissociate fully or >50% dissociate

• H₂SO₄ Sulphuric acid

• HCl Hydrochloric acid

• HNO₃ Nitric acid

Define a weak acid and name 3

An acid where the acid particles dont fully dissociate <50% dissociated

• CH₃COOH ethanoic acid

• Citric acid

• Carbonic acid

How much does the concentration of H⁺ change per pH number

10x H+ so the concerntration from 3 to 2 is 10x greater

Metal + Acid —→

Salt + Hydrogen

Metal Oxide + Acid —>

Salt +Water

Metal Hydroxide + acid —>

Salt + Water

Metal Carbonate + acid —>

Salt + water + co₂

What is a displacement reaction

When a more reactive metal displaces a less reactive metal

Define oxidisation

• The gain of oxygen

• The loss of electrons

Define Reduction

• The loss of oxygen

• The gain of electrons

Define ionic equation

The removal of spectator ions from an equation

How do you write a half equation

only include the changes in charge of an element

Fe²⁺+2e^- —> Fe

Ca —> Ca²⁺ +2e

What does PANIC stand for in electrolysis

Positive

Anode

Negative

Is

Cathode

Define an electrolyte for electrolysis

Liquid or solution that contains an ionic compound, with ions that are free to move to the elctrodes.

What happens at the Anode

Anions(negative ions) loose electrons/oxidise

What happens at the Cathode

Cations(positive ions) gain electrons/reduce

What is Produced at the cathode

• The Least reactive element will be formed, hydrogen if it is less reactive than the metal

What is produced at the anode

• Oxygen will be produced at the anode unless a halide ion is present