Metal oxides are bases. In general, when an acid reacts with a metal oxide, the products are a salt and water.
Acid + metal oxide → salt + water
Sulfuric acid + copper oxide → copper sulfate + water
H2SO4(aq) + CuO(s) → CuSO4(aq) + H2O(l)
Alkalis are soluble bases. A salt and water are produced when acids react with alkalis. In general:
Acid + alkali → salt + water
Nitric acid + sodium hydroxide → sodium nitrate + water
HNO3(aq) + NaOH(aq) → NaNO3(aq) + H2O(l)
A salt, water and carbon dioxide are produced when acids react with carbonates. In general:
Acid + carbonate → salt + water + carbon dioxide
Hydrochloric acid + copper carbonate → copper chloride + water + carbon dioxide
2HCl(aq) + CuCO3(s) → CuCl2(aq) + H2O(l) + CO2(g)
The name of a salt has two parts. The first part comes from the base, alkali or metal carbonate. The second part comes from the acid:
Predict the name of the salt formed when copper oxide reacts with nitric acid.
The salt formed is copper nitrate.
|Charge on ion||Examples|
|+1||K+, Na+, Li+|
|+2||Mg2+, Ca2+, Cu2+, Fe2+|
|-1||Cl-, Br-, I-, NO3-|
Notice that ions of group 1 elements have a charge of +1, and ions of group 2 elements have a charge of +2. The group 7 element ions have a charge of -1, and the group 6 element ions have a charge of -2.
What is the formula of aluminium sulfate?
The formulae of the ions are Al3+ and SO42-.
The sum of the charges on the ions in the neutral salt must be zero. Two Al3+ ions have a total charge of +6 and three SO42- ions have a total charge of -6.
So the formula is Al2(SO4)3.
What is the formula of magnesium chloride?