1. What is Mole Fraction of Solvent?

Definition: Mole fraction of solvent is the ratio of the number of moles of solvent to the total number of moles of solute and solvent in a solution.

Purpose: It helps in understanding the composition of solutions and is particularly important in studying colligative properties like vapour pressure lowering.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( x_2 \) — Mole fraction of solvent
• \( p \) — Vapour pressure of solvent in solution (Pa)
• \( p_0 \) — Vapour pressure of pure solvent (Pa)

Explanation: The vapour pressure of the solvent in solution is divided by the vapour pressure of the pure solvent to determine the mole fraction of the solvent.

3. Importance of Mole Fraction Calculation

Details: Mole fraction is crucial for understanding solution behavior, predicting vapour pressure changes, and calculating other colligative properties like boiling point elevation and freezing point depression.

4. Using the Calculator

Tips: Enter the vapour pressure of the solvent in solution and the vapour pressure of the pure solvent. Both values must be > 0 and the solution pressure cannot exceed the pure solvent pressure.

5. Frequently Asked Questions (FAQ)

Q1: What does the mole fraction represent?
A: It represents the proportion of solvent molecules in the entire solution, ranging from 0 to 1.

Q2: Why does vapour pressure decrease when solute is added?
A: Solute particles reduce the number of solvent molecules at the surface, lowering the escaping tendency (vapour pressure).

Q3: What's the range of possible mole fraction values?
A: Mole fraction always ranges between 0 (pure solute) and 1 (pure solvent).

Q4: How is this related to Raoult's Law?
A: This calculation is a direct application of Raoult's Law for ideal solutions.

Q5: Can I use different pressure units?
A: Yes, as long as both pressures are in the same units, the ratio (mole fraction) will be correct.