Metal oxides contain atoms of a metal combined with atoms of oxygen. The black powder copper oxide is an example of a metal oxide.
Copper Oxide Powder
Metal oxides react with acids to produce a salt and water. This can be shown in an equation:
Acid + Metal oxideSalt + Water
The salt produced from these reactions is dependent on the acid that is used. Metal oxides form chloride salts when reacting with hydrochloric acid, nitrate salts when reacting with nitric acid and sulfate salts when reacting with sulfuric acid.
An example of each type of salt formed is shown in the equations below:
Hydrochloric acid + sodium oxideSodium chloride + Water
HCl+ Na2ONaCl + H2O
Sulfuric acid + calcium oxidecalcium sulfate + Water
H2SO4+ CaOCaSO4 + H2O
Nitric acid + copper oxidecopper nitrate + Water
HNO3+ CuOCu(NO3)2 + H2O
It is important to learn the formulas of the acids, as they are the three most commonly used acids in the science lab.