# What is the vapor in oxygen gas collected by water displacement at 10°C and 75 mm Hg?

${P}_{\text{measured}}$ $=$ ${P}_{\text{gas"+P_"SVP}}$
Any gas collected by water displacement will contain water vapour, the so-called $\text{saturated vapour pressure}$. This is extensively tabulated, and fat 10""^@ $C$, ${P}_{\text{SVP}} = 10.2 \cdot m m \cdot H g$
${P}_{\text{gas}}$ $=$ ${P}_{\text{measured"-P_"SVP}}$ $=$ $75 \cdot m m \cdot H g - 10.2 \cdot m m \cdot H g$ $=$ ??*mm*Hg