$1.\backslash ((4\backslash \%)\backslash )$ Consider the piston$/$cylinder arrangement as shown in the figure. At the top of the piston stroke, the air temperature is $\backslash (1000^\{\backslash$circ$\}\backslash$mathrm$\{$R$\}\backslash )$ and the pressure is $300$ psi $.$ The gas expands reversibly and adiabatically to atmospheric pressure as the piston moves downward. The final pressure is $20$ psia and the final temperature is $\backslash (600^\{\backslash$circ$\}\backslash$mathrm$\{$R$\}\backslash ).$ Calculate the entropy change for this process.