Colligative Properties

Physical changes that result from adding solute to a solvent

One property is Vapor-Pressure Lowering

Vapor-pressure lowering is when the vapor pressure of a pure solvent is greater than the vapor pressure of a solution containing a non-volatile liquid.

Information

Equation: Psolution= (χsolvent) (P°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


Facts:


  • 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



http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch15/colligative.php


http://www.chemistryexplained.com/Ce-Co/Colligative-Properties.html

Vapor- Pressure Lowering Continued




#4

Big image

Another property is Freezing-Point Depression

Freezing-point depression is described as the process in which adding a solute to a solvent decreases the freezing point of the solvent.
Big image

Information

Equation: ΔT = i Kf m


Molality: the concentration of a solution expressed in moles of solute per kilogram of solvent


Facts:


  • 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.



http://www.chemteam.info/Solutions/FP-depression.html

http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/meltpt.html

Big image
Big image

A third property is Boiling-Point Elevation

Boiling-point elevation describes the idea that the boiling point of a liquid will be higher when another compound is added, meaning that a solution has a higher boiling point than a pure solvent.
Big image

Information

Equation: ΔT= Kb m


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


Facts:

  • 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.


http://chemistry.about.com/od/solutionsmixtures/a/boilingpointele.-NxZ.htm

http://www.kentchemistry.com/links/Math/vant%20hoff.htm

Big image
Big image

The last property is Osmotic Pressure

Osmotic pressure is the pressure that has to be applied to a pure solvent to prevent it from passing into a given solution by osmosis.
Big image

Information

Equation: Π = iMRT


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


Facts:

  • 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

http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/ospcal.html


Big image
Big image