CHEM 2
Cards (12)
- Colligative propertiesProperties of a solution that depend only on the number and not on the identity of the solute particles
- ColligativeTied together (from Latin word "coligare")
- Colligative properties depend on the collective effect of the concentration of solute particles present in an ideal solution
- Types of Colligative Properties
- Vapor Pressure Lowering
- Boiling Point Elevation
- Freezing Point Depression
- Osmotic Pressure
- Vapor PressureThe pressure exerted by a vapor that is in dynamic equilibrium with its liquid in a closed system
- A solution that contains a solute that is nonvolatile (not easily vaporized)Always has a lower vapor pressure than the pure solvent
- Raoult's lawThe lowering of the vapor pressure by a non-volatile solute is directly proportional to the concentration of the solute added, the greater is the decrease of vapor pressure
- A certain volume of pure water is placed on one arm of the U-tube. The same volume is placed on the other arm of the U-tube. If the U-tube and its contents are allowed to stand for a few minutes, it will be noted that the level of the pure water and the sugar solution in the U-tube will differ from each other. The level of sugar solution is higher compared to the level of the pure water. This means that the volume of the sugar solution has increased, while that of pure water has decreased.
- Ideal solutionA solution that follows Raoult's law
- Non-ideal solutionA solution that forms 2 or more species during mixing with the solvent
- Van 't Hoff factorThe ratio between the actual concentration of particles produced when the substance is dissolved and the concentration of a substance as calculated from its mass
- For two or more species it is considered non-ideal, the Van't Hoff factor (i) is needed. Example, i = 2 for NaCl and K2SO4, i = 3 for MgCl2, CaCl2, and K2SO4; and i = 5 for Fe3(PO4)2. This is important especially on calculations involving non-ideal solution to get an accurate result from experimental values.