Molarity and Molality
Molarity and molality are both concentration measures used in chemistry to express the amount of solute in a given amount of solvent.

Molarity (M)
- Molarity is defined as the number of moles of solute per liter of solution. It is expressed in moles per liter (mol/L).
- The formula for molarity is: Molarity (M) = moles of solute / volume of solution in liters.
- Molarity is temperature dependent and changes with temperature due to the change in volume.

Molality (m)
- Molality is defined as the number of moles of solute per kilogram of solvent. It is expressed in moles per kilogram (mol/kg).
- The formula for molality is: Molality (m) = moles of solute / mass of solvent in kilograms.
- Molality is not temperature dependent, making it a more useful measure for certain applications.

Numericals based on Molarity and Molality
1. Calculate the molarity of a solution containing 0.5 moles of NaCl in 2 liters of water.
Molarity = moles of solute / volume of solution
Molarity = 0.5 moles / 2 L = 0.25 M
2. Calculate the molality of a solution containing 0.2 moles of glucose in 100 grams of water.
Molality = moles of solute / mass of solvent
Molality = 0.2 moles / 0.1 kg = 2 mol/kg
In conclusion, molarity and molality are important concepts in chemistry that help quantify the concentration of solutions. Understanding these measures is crucial for various chemical calculations and experiments.