The normal boiling point of methanol is 64.7oC. A solution containing a nonvolatile solute dissolved in methanol has a vapor pressure of 670.0 torr at 64.7oC. What is the mole fraction of methanol in this solution?
64
12.44
So what was the correct answer because i have no clue how to do this
To find the mole fraction of methanol in the solution, we can use Raoult's law, which states that the vapor pressure of a solution is proportional to the mole fraction of the solvent.
The vapor pressure of the solution is given as 670.0 torr, which is equal to the vapor pressure of pure methanol at its boiling point. This means that the nonvolatile solute does not contribute to the vapor pressure.
According to Raoult's law, the vapor pressure of the solution is given by:
P solution = P solvent * X solvent
Where:
P solution is the vapor pressure of the solution
P solvent is the vapor pressure of the solvent (pure methanol in this case)
X solvent is the mole fraction of the solvent (methanol)
Since the vapor pressure of the solution matches the vapor pressure of pure methanol, we can set up the following equation:
670.0 torr = 64.7oC * X solvent
Now, we can solve for X solvent, which represents the mole fraction of methanol in the solution.
X solvent = 670.0 torr / 64.7oC
X solvent = 10.35
The mole fraction of methanol in this solution is approximately 10.35.