Other Properties of Solutions Molality -Molality is similar to molarity except that molality expresses moles of solute dissolved in a kilogram of solvent rather than in a liter of solution -molality is the amount of solute present divided by the amount of solvent present. -Molality is a convenient measure because it does not depend on volume and therefore does not change with temperature. Molality = __moles__ kilograms
Other Properties of Solutions Colligative Properties -When a pure solid is dissolved in a solvent, several physical properties of that solvent change depending on the amounts of the solute to solvent present; these properties are colligative properties -There are four common colligative properties: boiling point elevation, freezing point depression, vapor pressure reduction, and osmosis
Other Properties of Solutions -The freezing point and boiling point of a solution are directly proportional to the concentration of the solution in molality Ex: salt, such as sodium chloride or calcium chloride, is sprinkled on icy roads to lower the freezing point of water and melt the snow or ice. -The freezing point is lowered (depressed) in proportion to the amount of solute dissolved -Boiling points can be raised (elevated) in proportion to the amount of solute added also
Other Properties of Solutions Saturation -saturation is the point at which a solution of a substance can dissolve no more of that substance and additional amounts of it will appear as a separate phase -This point of maximum concentration (or saturation point) depends on the temperature, pressure, and chemical nature of the substances involved