Calculate the amount of oxygen required for complete oxidation of 8.0 g of calcium.

The equation for the reaction of calcium with oxygen:

2Ca + O2 = 2CaO

Amount of calcium substance:

v (Ca) = m (Ca) / M (Ca) = 8/40 = 0.2 (mol).

According to the reaction equation, 2 mol of Ca reacts with 1 mol of O2, therefore:

v (O2) = v (Ca) / 2 = 0.2 / 2 = 0.1 (mol).

Thus, the required volume of oxygen, measured under normal conditions (n.o.):

V (O2) = v (O2) * Vm = 0.1 * 22.4 = 2.24 (l).

Answer: 2.24 l.