Relative Lowering of Vapour Pressure Formula:
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Definition: The Relative Lowering of Vapour Pressure is the lowering of vapour pressure of pure solvent on addition of solute.
Purpose: This calculation helps in understanding colligative properties of solutions and is important in chemical engineering and physical chemistry.
The calculator uses the formula:
Where:
Explanation: The Van't Hoff factor accounts for the number of particles the solute dissociates into, while the mole ratio determines the relative effect on vapour pressure.
Details: Understanding vapour pressure lowering is crucial for predicting boiling point elevation, freezing point depression, and osmotic pressure of solutions.
Tips: Enter the Van't Hoff factor (default 1.008 for non-electrolytes), moles of solute, and moles of solvent (default 10). All values must be > 0.
Q1: What is the Van't Hoff factor?
A: It's the ratio of observed colligative property to theoretical colligative property, accounting for solute dissociation.
Q2: What's a typical Van't Hoff factor value?
A: For non-electrolytes it's 1, for strong electrolytes it's the number of ions produced (e.g., 2 for NaCl).
Q3: Why is relative lowering important?
A: It's a fundamental colligative property that helps determine solution behavior regardless of solute nature.
Q4: How do I find the number of moles?
A: Moles = mass (g) / molar mass (g/mol). Use our Molar Mass Calculator if needed.
Q5: Does this work for concentrated solutions?
A: This formula works best for dilute solutions. For concentrated solutions, activity coefficients must be considered.