Vapor pressures of ethanol and 1 propanol at 35 C are 100 and 37.6. Calculate partial pressures of ethanol and 1-propanol at 35 C over ethanol in 1-propanol, where the mole fraction of ethanol is .3

Question

its in ideal behavior

Answer 1

Mole fraction ethanol = 0.3

Mole fraction propanol = 1 - 0.3 = 0.7

Vapor pressure = mole fraction x vapor pressure of pure solvent

Vapor pressure of ethanol = 0.3 x 100 = 30 whatever units you were given

Vapor pressure of propanol = 0.7 x 37.6 = 26.3 whatever units you were given

Answer 2

If you assume an ideal solution, Raoult's Law applies: P_i = x_iP_VP,i for volatile components in a solution.

P_eth = .3 * 100 (Units? mmHg?)

P_prop =.7*37.6

The gas will be richer in ethanol because it is more volatile (has a greater vapor pressure)