An engine using 1 mol of an ideal gas initially at 19.6 L and 366 K performs a cycle
consisting of four steps:
1) an isothermal expansion at 366 K from
19.6 L to 41.3 L ;
2) cooling at constant volume to 204 K ;
3) an isothermal compression to its originalvolume of 19.6 L; and
4) heating at constant volume to its original
temperature of 366 K .
Find its efficiency. Assume that the
heat capacity is 21 J/K and the universal gas constant is 0.08206 L · atm/mol/K =
8.314 J/mol/K. Give your answer in the form
of a percentage.