We limit our discussion to calculation of the amout of work involved when a system expands or contracts against a constant pressure.
Calculating the Amount of Expansion Work at Constant Pressure Associated With a Volume Change
Note: It may be necessary to convert the volumes to cubic meters.
Note: If the pressure has units of Pascals and the volume units of m3, the work will have units of Joules. Work done by a system (as the system expands) has a negative value. Work done on a system (as the system shrinks) has a positive value.