# If iron (II) oxide gas decomposes into iron liquid and oxygen gas and 6 moles of iron (II) oxide gas are used, how of liters of oxygen gas are produced?

The reaction equation is: $2 F e O \to 2 F e + {O}_{2}$
This means that for $6 m o l$ of $F e O$, only $3 m o l {O}_{2}$ is produced (half the moles).
E.g. : If you cooled it down to ${0}^{o} C$ and get it to standard atmospheric pressure the volume would be $3 \cdot 22.4 L = 67.2 L$