Osmolality can be defined as a measure of the concentration of a solution based on which factor?

Osmolality can be defined as a measure of the concentration of a solution based on which factor?

• A. Number of dissolved particles
• B. Number of ionic particles present
• C. Number and size of the dissolved particles
• D. Density of the dissolved particles

Answer: (A)

Osmolality reflects how concentrated a solution is by counting how many solute particles are present that affect osmotic pressure. It’s defined as osmoles of solute per kilogram of solvent, so what matters is the total number of dissolved particles, not their size or whether they are ions. If a solute dissociates, it increases the particle count and raises osmolality accordingly. Nonionic solutes contribute one particle per molecule, while electrolytes that dissociate add more particles per mole. Density has no role in this measurement. Therefore, the factor is the number of dissolved particles.

Osmolality reflects how concentrated a solution is by counting how many solute particles are present that affect osmotic pressure. It’s defined as osmoles of solute per kilogram of solvent, so what matters is the total number of dissolved particles, not their size or whether they are ions. If a solute dissociates, it increases the particle count and raises osmolality accordingly. Nonionic solutes contribute one particle per molecule, while electrolytes that dissociate add more particles per mole. Density has no role in this measurement. Therefore, the factor is the number of dissolved particles.