Molality

Definition

Molality is a measure of the concentration of a solute in a solution, expressed as moles of solute per kilogram of solvent. It is used in chemistry and biology to describe solutions where temperature variations are significant.

5 Must Know Facts For Your Next Test

1. Molality is independent of temperature because it depends on mass rather than volume.
2. It is an important measure in studying colligative properties such as boiling point elevation and freezing point depression.
3. Molality is symbolized by 'm' and is calculated using the formula m = moles of solute / kilograms of solvent.
4. In osmoregulation, molality helps in understanding how organisms maintain fluid balance in varying environments.
5. Unlike molarity, which can change with temperature due to volume expansion or contraction, molality remains constant.

Review Questions

• What is the main advantage of using molality over molarity in experiments involving temperature changes?
• How does molality contribute to understanding colligative properties?
• Why might biologists prefer using molality when studying osmotic balance?

Related terms

Molarity: A measure of concentration expressed as moles of solute per liter of solution.

Osmoregulation:

The process by which organisms regulate the water and electrolyte balance within their bodies.

Colligative Properties: Properties that depend on the number of solute particles in a solution rather than the nature of the particles themselves.