Molecular Mass Solute Formula:
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Definition: This calculator determines the molecular mass of a solute in a solution based on the relative lowering of vapour pressure.
Purpose: It helps chemists and researchers determine the molecular mass of unknown solutes by measuring vapour pressure changes.
The calculator uses the formula:
Where:
Explanation: The formula relates the molecular mass of the solute to the change in vapour pressure caused by its addition to the solvent.
Details: Determining molecular mass is fundamental in chemistry for identifying substances, calculating concentrations, and understanding solution properties.
Tips: Enter all required values in appropriate units. Ensure vapour pressure of pure solvent is greater than in solution. Default values are provided for common solvents like water.
Q1: Why does adding solute lower vapour pressure?
A: Solute particles occupy space at the surface, reducing solvent molecules that can escape into vapour phase (Raoult's Law).
Q2: What's a typical molecular mass for water as solvent?
A: Water has a molecular mass of approximately 0.018 kg/mol (18 g/mol).
Q3: What units should I use for this calculator?
A: Use consistent units (kg for masses, Pa for pressures) as shown in the input fields.
Q4: Can I use this for non-volatile solutes only?
A: Yes, this calculation is most accurate for non-volatile solutes that don't contribute to vapour pressure.
Q5: What if my vapour pressures are equal?
A: The formula requires \( p_o > p \). Equal pressures would mean no solute effect (infinite molecular mass).