The elementary analysis of alcohols by combustion

Exercise 1

What volume of oxygen (STP) is required by the complete combustion of $3.1\;g$ glycol?

Equation: $C_2H_6O_2$ $+$ $\frac{5}{2}O_2$ $\rightarrow$ $2CO_2$ $+$ $3H_2O$ $n_{alcohol}$ $=$ $\frac{3.1}{62}=0.05\;mol$ $n_{O_2}$ $=$ $0.05\frac{5}{2}=0.125\;mol$ $V_{O_2}$ $=$ $0.125\cdot 22.4$ $=$ $2.8\;L$