Physical changes that result from adding solute to a solvent
Raoult's Law: this law states that the solvent over the solution is proportional to the fraction of solvent molecules in the solution, only when two-thirds of the molecules are solvent molecules
- Colligative properties depend on how many solute particles are present in the solvent and do not depend on the type of solute particles.
- Colligative properties are intensive properties
Another property is Freezing-Point Depression
Equation: ΔT = i Kf m
Molality: the concentration of a solution expressed in moles of solute per kilogram of solvent
- Kf is the freezing-point depression constant
- The freezing point of pure water is 0°C , but just by adding a solvent like salt, the freezing point will lower.
A third property is Boiling-Point Elevation
Van't Hoff Factor: the ratio between the actual concentration of particles produced when the substance is dissolved, and the concentration of a substance as calculated from its mass
- Kb is the boiling-point elevation constant
- The amount of boiling point elevation can be calculated using the Clausius-Clapeyron equation and Raoult's Law.
The last property is Osmotic Pressure
Osmosis: a passage of a solvent from a lower-concentration solution to a higher-concentration solution, through a semi-permeable membrane, separating the two solutions
- Osmotic pressure is necessary in plant cells to keep their support.
- Osmotic pressure obeys the same relationship of the same form as the ideal gas law