Plot $($not sketch$--$create an actual plot!$)$ three van der Waals isotherms $($P vs$.$ V$)$ for three different values of T: carbon dioxide at Tc$,$ Tc$-50$ K$,$ and Tc $+50$K on a single plot with a volume range of $0\mathrm{.}05$ to $0\mathrm{.}6$ L$/$mol$.$ You may use any appropriate software to plot pressure values from $-10$ to from $-10$ to $140$ atm. Use the resulting graph to estimate Pc and Vc$,$ and comment on the features of the graph.