A quantity of methyl acetate is placed in an open, transparent, three-liter flask and boiled long enough to purge all air from the vapor space. The flask is then sealed and allowed to equilibrate at 30°C, at which temperature methyl acetate has a vapor pressure of 269 mm Hg. Visual inspection shows 10mL of liquid methyl acetate present.

(a) What is the pressure in the flask at equilibrium? Explain your reasoning.

(b) What is the total mass (grams) of methyl acetate in the flask? What fraction is in the vapor phase at equilibrium?

(c) The above answers would be different if the species in the vessel were ethyl acetate because methyl acetate and ethyl acetate have different vapor pressures. Give a rationale for that difference.