Complete the chemical equations for the reactions when tin and aluminum are heated. (Hint: Aluminum oxide is Al2O3 and tin oxide is SnO.)

The equation for the formation of aluminum oxide from aluminum and oxygen by beating aluminum in the presence of air is:

The reason that the formula of aluminum oxide is Al2O3 is because aluminum forms a +3 ion and oxygen forms a -2 ion. Elemental oxygen is diatomic, meaning that it exists in nature as O2. The subscripts of substances can't be changed so coefficients (multipliers) have to be added to balance the equations.

The equation for the formation of tin(II)oxide by heating tin in air is:

Again, coefficients must be added to have the same number of atoms on each side of the equation. Subscripts can't be changed because they are a quantitative description of the substance.