1. What is Molecular Mass of Solvent Calculator?

Definition: This calculator determines the molecular mass of a solvent based on the relative lowering of vapour pressure when a solute is added.

Purpose: It helps chemists and researchers understand colligative properties of solutions and determine molecular masses of solvents.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( M \) — Molecular mass of solvent (kg)
• \( p_o \) — Vapour pressure of pure solvent (Pa)
• \( p \) — Vapour pressure of solvent in solution (Pa)
• \( m \) — Molality of the solution (mol/kg)

Explanation: The formula relates the lowering of vapour pressure to the molecular mass of the solvent through Raoult's Law.

3. Importance of Molecular Mass Calculation

Details: Determining molecular mass is fundamental in chemistry for understanding solution properties, reaction stoichiometry, and material characterization.

4. Using the Calculator

Tips: Enter the vapour pressures in Pascals and molality in mol/kg. Ensure vapour pressure in solution is less than pure solvent's vapour pressure.

5. Frequently Asked Questions (FAQ)

Q1: What is relative lowering of vapour pressure?
A: It's the ratio of vapour pressure lowering (p₀-p) to the original vapour pressure (p₀) of the pure solvent.

Q2: Why is molality used instead of molarity?
A: Molality (moles solute/kg solvent) is temperature-independent, making it more reliable for colligative property calculations.

Q3: What units should I use for this calculation?
A: Use Pascals for vapour pressures, mol/kg for molality, and the result will be in kilograms (though often reported in g/mol).

Q4: Does this work for all solvents?
A: This applies to ideal solutions where Raoult's Law holds. For non-ideal solutions, activity coefficients must be considered.

Q5: How accurate is this method?
A: It provides good estimates for dilute solutions. Accuracy decreases with increasing solute concentration.