If a solution has a vapor pressure of 80 mmHg and the pure solvent has a vapor pressure of 100 mmHg, what is the mole fraction of the solvent?
Practice Questions
1 question
Q1
If a solution has a vapor pressure of 80 mmHg and the pure solvent has a vapor pressure of 100 mmHg, what is the mole fraction of the solvent?
0.8
0.75
0.6
0.5
Using Raoult's Law, the mole fraction of the solvent can be calculated as 80 mmHg / 100 mmHg = 0.8, which corresponds to a mole fraction of 0.75 for the solvent.
Questions & Step-by-step Solutions
1 item
Q
Q: If a solution has a vapor pressure of 80 mmHg and the pure solvent has a vapor pressure of 100 mmHg, what is the mole fraction of the solvent?
Solution: Using Raoult's Law, the mole fraction of the solvent can be calculated as 80 mmHg / 100 mmHg = 0.8, which corresponds to a mole fraction of 0.75 for the solvent.
Steps: 10
Step 1: Understand that vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid at a given temperature.
Step 2: Identify the vapor pressure of the solution, which is given as 80 mmHg.
Step 3: Identify the vapor pressure of the pure solvent, which is given as 100 mmHg.
Step 4: Use Raoult's Law, which states that the vapor pressure of a solution is equal to the mole fraction of the solvent times the vapor pressure of the pure solvent.
Step 5: Set up the equation: Vapor pressure of solution = (Mole fraction of solvent) x (Vapor pressure of pure solvent).
Step 6: Substitute the known values into the equation: 80 mmHg = (Mole fraction of solvent) x 100 mmHg.
Step 7: Solve for the mole fraction of the solvent by dividing both sides by 100 mmHg: Mole fraction of solvent = 80 mmHg / 100 mmHg.
Step 8: Calculate the mole fraction: Mole fraction of solvent = 0.8.
Step 9: Since the mole fraction of the solvent is 0.8, the mole fraction of the solute can be found by subtracting from 1: Mole fraction of solute = 1 - 0.8 = 0.2.
Step 10: Verify that the mole fraction of the solvent is indeed 0.8, which corresponds to the correct calculation.
