Here's a breakdown:
* Molality (m): The concentration of a solution expressed as the number of moles of solute per kilogram of solvent.
* Solute: The substance that is being dissolved.
* Solvent: The substance that dissolves the solute.
Example:
A solution containing 0.5 moles of glucose dissolved in 1 kg of water has a molality of 0.5 m.
Why use molality?
* Independent of temperature: Molality is independent of temperature changes because it's based on mass, which doesn't change with temperature.
* Useful for colligative properties: Molality is used to calculate colligative properties like freezing point depression and boiling point elevation, which are related to the concentration of solute particles in a solution.
Key difference from molarity:
* Molarity (M): Moles of solute per liter of *solution* (solute + solvent). Molarity is dependent on temperature as volume changes with temperature.
