# "H"_ 2"O"_((l)) rightleftharpoons "H"_2"O"_((g)) What happens when this system reaches equilibrium?

Dec 20, 2016

The water gas will express a $\text{saturated vapour pressure}$.

#### Explanation:

IF you collect a gas over water, you always have to take into account ${P}_{\text{SVP}}$, the $\text{saturated}$ or $\text{equilibrium vapour pressure}$ for a given temperature. ${P}_{\text{SVP}}$ values are extensively tabulated. Would you expect ${P}_{\text{SVP}}$ to rise or fall with temperature? At a temperature of $100$ ""^@C, can you quote ${P}_{\text{SVP}}$?