Final answer:
Molarity is the concentration of solute per liter of solution, while molality is the concentration of solite per kilogram of solvent. In dilute aqueous solutions, these concentrations are similar because the density of water is close to 1 g/mL.
Step-by-step explanation:
Molarity is one mole of solute dissolved in water to make 1 L of solution, while molality is one mole of solute dissolved in one kg of water.
Molarity and molality are two different ways to express the concentration of a solution. Molarity (M) is defined as the number of moles of solute per liter of solution. On the other hand, molality (m), refers to the number of moles of solute per kilogram of solvent. In dilute solutions, where water is the solvent, these two measurements are very close to each other because the density of water is approximately 1.0 g/mL, so the volume of 1 kg of water is about 1 L.