Home
Back
Water Molality Formula:
| From: | To: |
Molality (m) is a measure of the concentration of a solute in a solution, defined as the number of moles of solute per kilogram of solvent (usually water in aqueous solutions). Unlike molarity, molality is not affected by temperature changes because it's based on mass rather than volume.
The calculator uses the molality formula:
Where:
Explanation: The formula simply divides the number of moles of solute by the mass of the water solvent in kilograms.
Details: Molality is particularly important in colligative property calculations (boiling point elevation, freezing point depression) and in situations where temperature varies, as it remains constant unlike molarity which changes with temperature.
Tips: Enter the amount of solute in moles and the mass of water in kilograms. Both values must be positive numbers.
Q1: What's the difference between molality and molarity?
A: Molality (m) is moles of solute per kilogram of solvent, while molarity (M) is moles of solute per liter of solution. Molarity changes with temperature, molality doesn't.
Q2: When should I use molality instead of molarity?
A: Use molality when working with temperature-sensitive applications or colligative properties. Use molarity for most general chemistry applications.
Q3: Can I use grams instead of moles for the solute?
A: You'll need to convert grams to moles using the solute's molar mass before using this calculator.
Q4: Does the calculator work for solvents other than water?
A: Yes, the formula works for any solvent, though the result would technically not be called "molality in water."
Q5: What are typical molality values for common solutions?
A: For aqueous solutions, molality typically ranges from 0.1 to 6 mol/kg, though more concentrated solutions are possible.