[ichidp]

Myristic acid is to be distilled at 200C using superheated steam. It may be assumed that the relative saturation of the steam with acid vapors will be 80%. Calculate the weight of the steam required to vaporize one pound of acid if the distillation is conducted at 740 mmHg. The vapor pressure of the pure liquid at 200C is 14.5 mmHg. (Note that the relative saturation is the ratio of the partial pressure of the vapor to the vapor pressure of the pure liquid at the given temperature multiplied by 100).

enlighten me on this one please.