Short Answer 
Vapor pressure is crucial for understanding how a non-volatile solute impacts a solvent, leading to the concept of relative lowering of vapor pressure, defined as the decrease in vapor pressure relative to the pure solvent. The mole fraction of the non-volatile solute can be calculated using the formula ŒiP/P‚CA, resulting in a mole fraction of 0.0225 based on given values.
Step 1: Understanding Vapor Pressure
The concept of vapor pressure is critical in understanding how a non-volatile solute affects a solvent. Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid or solid phase. In solutions, a non-volatile solute decreases the vapor pressure of the solvent, which is essential for calculating the properties of the solution.
Step 2: Relative Lowering of Vapor Pressure
The relative lowering of vapor pressure is defined as the ratio of the decrease in vapor pressure to the vapor pressure of the pure solvent. This can be represented mathematically as:
- ŒiP: lowering of vapor pressure
- P0: vapor pressure of the pure solvent
- Xs: mole fraction of the solute
The relationship can be expressed with the equation: ŒiP/P0 = Xs, where Xs represents the mole fraction of the solute.
Step 3: Calculating Mole Fraction of Non-Volatile Solute
To find the mole fraction of the non-volatile solute in your solution, plug in the provided values into the equation. Given the value of the relative lowering of vapor pressure as 0.0225:
- Xs = ŒiP/P0 = 0.0225
This directly shows that the mole fraction of the non-volatile solute is 0.0225, which indicates the composition of the solute in the solution effectively.