Answer
65 atm
Work Step by Step
$V=2.00\,L$
$n= 7.0\,mol$
$T=(50+273)K=323\,K$
$R=0.0821\,L\,atm\,mol^{-1}K^{-1}$
For $CO_{2}$, $a=3.59\,L^{2}\,atm/mol^{2}$
and $b=0.0427\,L/mol$
$(P+\frac{n^{2}a}{V^{2}})(V-nb)=nRT$ (van der Waals equation)
$\implies P=(\frac{nRT}{V-nb})-(\frac{n^{2}a}{V^{2}})$
$=[\frac{(7.0\,mol)(0.0821\,L\,atm\,mol^{-1}K^{-1})(323\,K)}{2.00\,L-(7.0\,mol\times0.0427\,L/mol)}]-[\frac{(7.0\,mol)^{2}(3.59\,L^{2}\,atm/mol^{2})}{(2.00\,L)^{2}}]$
$=65\,atm$
