Calculate the density of ${\mathrm{CO}}_2$ at ${100}^{\circ }\mathrm{C}$ and 800 mm pressure $\mathrm{Hg}$ pressure  

$\mathrm{P}=800\mathrm{mm}\times \frac{1\mathrm{atm}}{760\mathrm{mm}}=\frac{80}{76}\mathrm{atm}$

1 mole of ${\mathrm{CO}}_2=12+(2\times 16)=44\mathrm{g}{\mathrm{mol}}^{-}$

                            $\begin{array}{l}\mathrm{R}=0.0821{\mathrm{LatmK}}^{-}{\mathrm{mol}}^{-};\\ \mathrm{T}=100+273=373\mathrm{K}.\end{array}$

We know that : $\mathrm{PV}=\mathrm{nRT} =\frac{\mathrm{W}}{\mathrm{M}}\mathrm{RT} ; \mathrm{P}=\frac{\mathrm{W}}{\mathrm{V}}\times \frac{\mathrm{RT}}{\mathrm{M}} = \frac{\mathrm{dRT}}{\mathrm{M}}$

$$\begin{gathered} \therefore \mathrm{d}=\frac{\mathrm{PM}}{\mathrm{RT}} \\ \mathrm{d}=\frac{44\times 80}{0.0821\times 373\times 76}=1.512\mathrm{g} {\mathrm{L}}^{-} \end{gathered}$$