For a perfect gas, the work of isothermal reversible expansion is given by

Where V_f / V_i is the ratio of final volume to initial volume, n is the amount of gas molecules (mol), T is the temperature (kelvin), and R is the gas constant (J K^-1 mol^-1).

Note that, for a given change of volume and fixed amount of gas, the work is greater the higher the temperature.

To graph work (J) enter the parameters (i.e., n and T) and hit New Plot. Up to 5 plots can be displayed at one time. The Clear button will remove all plots. To see the parameters for each plot hit the Legend on/off button. The Redraw button will refresh the graph. This is useful when the function domain (i.e., V_f / V_i ) has been changed. To see the value of each plot at a given point, move your cursor to the desired location then click and hold.