Pure n-butane is contained in an isothermal pressure cell in which the volume can be varied. The cell is maintained at 200oF as well as the volume is changed until the first drops of liquid n-butane form. Explain what is the pressure of the cell? The volume is decreased until the cell is essentially full of liquid n-butane with one a few bubbles of n-butane gas remaining. Explain what is the pressure of the cell?