Propane at 8 bars and 80 °c is contained in a closed, rigid vessel with a volume of 10 m3. its temperature drops due to heat transfer to the surroundings. determine (a) the temperature at which condensation first occurs and (b) the fraction of the total mass that has condensed when the pressure reaches 5 bars. also, find the volume occupied by saturated liquid (in m3) when the pressure reaches 5 bars.