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Acids, bases and salts - (CCEA)Reactions of acids

Many chemicals are acidic, neutral or alkaline. We can distinguish one from another using indicators. Acidity and alkalinity are measured on the pH scale. A salt is formed when an acid is neutralised by an alkali.

Part of Chemistry (Single Science)Structures, trends, chemical reactions, quantitative chemistry and analysis

Reactions of acids

Some general observations can be made during acid reactions:

if a gas is produced, the observations is ‘b�ܲ��’.
if a solid such as a solid metal, base or carbonate reacts with the acid then the observation is ‘solid disappears and a solution is produced’.
most acid reactions are exothermic – the observation is ‘heat released’. Exceptions – copper(II) oxide and sodium hydrogencarbonate with acid.

It is useful to know the colour of some compounds commonly reacted with acids to work out if a colour change has occurred.

Substance	Colour
copper(II) oxide	black solid
copper(II) carbonate	green solid
hydrated copper(II) sulfate	blue crystals
copper(II) salts in solution	blue solution
group 1, group 2, aluminium and zinc compounds	white solids – if they dissolve in water they give colourless solutions

Substance	copper(II) oxide
Colour	black solid

Substance	copper(II) carbonate
Colour	green solid

Substance	hydrated copper(II) sulfate
Colour	blue crystals

Substance	copper(II) salts in solution
Colour	blue solution

Substance	group 1, group 2, aluminium and zinc compounds
Colour	white solids – if they dissolve in water they give colourless solutions

Prescribed Practical C2 - Investigate the reaction of acids, including temperature changes that occur

Reaction of acids

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