Consider the chemical reaction:
$$2 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2 \mathrm{H}_{2}(g)+\mathrm{O}_{2}(g)$$
What mass of $\mathrm{H}_{2} \mathrm{O}$ is required to form 1.4 $\mathrm{L}$ of $\mathrm{O}_{2}$ at a temperature of 315 $\mathrm{K}$ and a pressure of 0.957 $\mathrm{atm}$ ?