Topic 4 - Chemical Changes

What colour is an acid or an alkaline in certain indicators?

Litmus: Acid - Red Alkaline - Blue

Methyl Orange: Acid - Red Alkaline - Yellow

Phenolphthalein: Acid - Colourless Alkaline - Pink

What are some examples of strong acids and weak acids?

Strong Acids:

Sulfuric

Hydrochloric

Nitric

Weak Acids:

Ethanoic

Citric

Carbonic

What is pH?

The measure of the concentration of Hydrogen Ions.

For every decrease of 1 on the pH scale, the concentration of hydrogen ions increase by a factor of 10.

So a pH 4 has 10 times the concentration of H+ ions than pH5

Reactions of acids:

Metal + Acid → Salt + Hydrogen

Metal Oxide + Acid → Salt + Water

Metal Hydroxide + Acid → Salt + Water

Metal Carbonate + Acid → Salt + Carbon Dioxide + Water

Metal + Water → Metal Hydroxide + Hydrogen

Ammonia + Acid → Ammonium Salt

What is the reactivity Series

The list of metals in order of reactivity towards other substances.

What are Oxidation, Reduction and Redox reactions?

Oxidation - Loss of electrons Or Gain of oxygen

Reduction - Gain of electrons Or Loss of oxygen

Redox - When electrons are transferred - O and R happen at the same time.

What is Electrolyosis?

The splitting of a dissolved or molten compound with electricity. There is the cathode (-) and anode (+) electrodes which attract the opposite charge ions and they react. This creates a flow of charge throughout the structure.

Describe an Aluminium Electrolyosis?

See image: