The vapor pressure of diethyl ether (ether) is 463.57 mm Hg at 25 °C. A nonvolatile, nonelectrolyte that dissolves in diethyl ether is aspirin. Calculate the vapor pressure of the solution at 25 °C when 14.88 grams of aspirin, C9H8O4 (180.1 g/mol), are dissolved in 269.2 grams of diethyl ether. diethyl ether = CH3CH2OCH2CH3 = 74.12 g/mol.

Explanation:

The vapor pressure of diethyl ether (ether) is 463.57 mm Hg at 25 °C. A nonvolatile, nonelectrolyte that dissolves in diethyl ether is aspirin. Calculate the vapor pressure of the solution at 25 °C when 14.88 grams of aspirin, C9H8O4 (180.1 g/mol), are dissolved in 269.2 grams of diethyl ether. diethyl ether = CH3CH2OCH2CH3 = 74.12 g/mol.

mol of C4H10O = mass of C4H10O / molar mass of C4H10O

= 242.1 g / 74.12 g/mol

= 3.266 mol

mol of C9H8O4 = mass of C9H8O4 / molar mass of C9H8O4

= 10.33 g / 180.1 g/mol

= 0.05736 mol

mole fraction of C4H10O,

X = mole of CHH1O0 / total mol

= (3.266)/(3.266 + 0.05736)

= 0.9827

now use:

P = Po*X

P = 463.57 * 0.9827

= 455.6 mm Hg