Colligative Properties of Solutions Optional

19 Given the freezing-point depression or hoiling-point elevation and the molality of a solution, or data from which they may be found, calculate the molal freezing-point constant or molal hoiling-point constant. 

A pure solvent has distinct physical properties, as does any pure substance. Introducing a solute into the solvent affects these properties. The properties of the solution depend on the relative amounts of solvent and solute. It has been found experimentally that, in dilute solutions of certain solutes, the change in some of these properties is proportional to the molal concentration of the solute particles. These are called col-ligative properties solution properties that are determined only by the number of solute particles dissolved in a fixed quantity of solvent. 

The change in a freezing point is the freezing-point depression, AT, (Fig. 16.20), and the change in a hoiling point is the hoiling-point elevation, AT. The two proportionalities and their corresponding equations are 

Hlhere is pure, colorless ice along the walls of the tube with concentrated solution in the center of the tube. 

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