Question

What volume does the molecules of a mole of water vapour actually occupies at STP?

Answer 1

Dear Student,

$$\begin{gathered} \mathrm{We}\mathrm{know}\mathrm{that}, \\ \mathrm{PV}=\mathrm{nRT} \\ \mathrm{or},\mathrm{V}=\frac{\mathrm{nRT}}{\mathrm{P}} \\ \mathrm{Here},\mathrm{n}=1 \\ \mathrm{and}\mathrm{at}\mathrm{STP} \\ \mathrm{T}=273\mathrm{K} \\ \mathrm{P}=1\mathrm{at}, \\ \mathrm{R}=0.0821{\mathrm{Latmmol}}^{-1}{\mathrm{K}}^{-1} \\ \mathrm{So},\mathrm{V}=\frac{1\times 0.0821\times 273}{1} \\ =22.4\mathrm{L} \end{gathered}$$
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