Calculate the volume of oxygen that will be released as a result of the thermal decomposition of NaNO3, weighing 100 g.

The reaction equation for the thermal decomposition of sodium nitrate:

2NaNO3 (t) = 2NaNO2 + O2

The amount of sodium nitrate substance:

v (NaNO3) = m (NaNO3) / M (NaNO3) = 100/85 (mol).

According to the reaction equation, 1 mol of O2 is released per 2 mol of NaNO3, therefore:

v (O2) = v (NaNO3) / 2 = (100/85) / 2 = 50/85 (mol)

and the volume of oxygen evolved under normal conditions (n.o.):

V (O2) = v (O2) * Vm = (50/85) * 22.4 = 13.2 (l).