4 moles of an ideal gas at 27°C are allowed to expand D isothermally from an initial pressure of 12.0 atm to a final pressure of 6.0 atm against a constant external pressure of 1.0 atm. Thus, work done will be

Gas is being expanded against external pressure. Thus, work is done by the system, work is negative.W=−pextV2−V1=−pext nRTp2−nRTp1=−nRTpext 1p2−1p1=−4×0.0821Latmmol−1K−1×116−112×300K=−8.21L atm =8.21Latm×8.314J0.0821L atm =−831.4J