Question

c) Estimate to the nearest degree temperature at which the vapor pressure of the solutions equals 1 atm

Answer 1

Solution.

According to the Raoult's law, the total vapor pressure of a solution is a sum of partial pressures of its components:

As 1 atm = 760 mmHg, we need to find the temperature when

X₁ and X₂ are mole fractions of the compounds 1 and 2 correspondingly.

First, using the experimental data on vapor pressures of each compound, and its mole fraction in the solution, the total pressure should be found.

After that the plot P = f(T) should be made in some math software.

Using the exponential trend line one can obtain the dependence P = f(T) in the form P =Ae^BT+C;

Solving this equation for temperature and using the pressure of 760, the temperature can be determined: