Question

What is the composition of a methanol (CH3OH) - propanol (CH3CH2CH2OH) solution that has a vapor pressure of 113 torr at 40 degrees C? At 40 degrees C, the vapor pressures of pure methanol and pure propanol are

303 and 44.6 torr, respectively. Assume the solution is ideal.

Answer 1

To find the composition of the methanol-propanol solution, we can use Raoult's law to calculate the mole fractions and vapor pressures of each component.

Step-by-step explanation:

To find the composition of the methanol-propanol solution, we can use Raoult's law. The mole fraction of methanol and propanol in the solution can be calculated using:

(a) Mole fraction of methanol (CH3OH) = moles of methanol / total moles in the solution
Moles of methanol = mass of methanol / molar mass of methanol
Total moles in the solution = moles of methanol + moles of propanol (CH3CH2CH2OH)
Repeat the same calculation for propanol.

(b) Using Raoult's law, the vapor pressure of methanol and propanol can be calculated:
Vapor pressure of methanol above the solution = mole fraction of methanol * vapor pressure of pure methanol
Vapor pressure of propanol above the solution = mole fraction of propanol * vapor pressure of pure propanol