Answer
Please see the work below.
Work Step by Step
We know that
$number \space of \space moles \space of water\space evaporated=\frac{PV}{RT}$
We plug in the known values to obtain:
$number \space of \space moles \space of water\space evaporated=\frac{0.2467\times 2.5}{0.0821\times 338}=0.0222moles$
$Mass\space of\space water \space evaporated=0.0222\times 18=0.40g$
