JESSICA BERGSTEDT, BRANDY DEBLIN, SARAH ZEHNDER

1

COLLIGATIVE PROPERTIES

• JESSICA BERGSTEDT, BRANDY DEBLIN, SARAH ZEHNDER

2

COLLIGATIVE PROPERTIES

• DEFINTION The properties of solutions that
  depend only on the number of particles present
  without regard to type
• FOUR PROERTIES
• 1. Fractional distillation
• 2. Osmosis and Osmotic pressure
• 3. Freezing point
• 4. Boiling point

3

FRACTIONAL DISTILLATION

• Definition A process by which components in a
  chemical mixture are separated according to their
  different boiling points. Vapors from a boiling
  solution are passed along a column. The
  temperature of the column gradually decreases
  along its length. Components with a higher
  boiling point condense on the column and return
  to the solution components with a lower boiling
  point pass through the column and are collected.

4

FRACTIONAL DISTILLATION

• In distillation, a liquid is converted into a
  vapor by heating it to its boiling point. The
  vapor is then cooled, usually by running water,
  and the condensed liquid is collected in a
  suitable separate container. The cold water which
  enters the condenser and flows around its inner
  tube condenses the vapor. The condensed vapor, or
  distillate, is collected in the receiving flask.
• More diagrams and information on fractional
  distillation

5

FRACTIONAL DISTILLATION

• Uses of distillation
• Petroleum refining is the process of separating
  the many compounds present in crude petroleum.
  The principle which is used that the longer the
  carbon chain the higher the temperature at which
  the compounds will boil. The crude petroleum is
  heated and then changed into a gas. The gases are
  passed through a distillation column which
  becomes cooler as the height increases. When a
  compound in the gaseous state cools below its
  boiling point, it condenses into a liquid. The
  liquids may be drawn off the distilling column at
  various heights.
• Diagram of crude oil distillation tower

6

Boiling Point

• Definition the temperature at which the vapor
  pressure of a liquid equals the atmospheric
  pressure.
• Example would be water boiling at 100 degrees
  Celsius.

7

Boiling Point

• Formula for boiling point and explanation

8

Boiling Point

• Calculating the change of degrees
• The slope of the boiling point line will be
  unique for every solvent.
• To calculate the number of degrees that a boiling
  point or melting point will change for some
  amount of solute, we must look up the boiling
  point and freezing point constants for our
  solvents in the following table.
• For more information and a boiling point diagram

9

Boiling Point
Molal Boiling Point Elevation and Freezing Point
Depression Constants

10

FREEZING POINT

• Definition The temperature at which a liquid
  undergoes a phase change from liquid to solid.
• The freezing point of water is 32 degrees Celsius.

11

FREEZING POINT

• The freezing point depression formula
• The symbol of the change in freezing point is
  negative because the freezing point solution is
  less than that of the pure solvent.
• More information on freezing point depression

12

FREEZING POINT
13

FREEZING POINT

• Raoults Law the vapor pressure of a solution is
  the product of the mole fraction of the solvent
  and the vapor pressure of the pure solvent.
• Ex) A vapor composition diagram is plotted at
  constant temperature a series of these plots at
  different temperatures is needed in order to
  obtain a boiling point/ composition diagram.
• When a solution is separated from a volume of
  pure solvent by a semi-permeable membrane that
  allows only the passage of solvent molecules, the
  height of the solution begins to rise. The value
  of the height difference between the two
  compartments reflects a property called the
  osmotic pressure of a solution.

14

OSMOSIS AND OSMOTIC PRESSURE

• Osmosis The phenomenon of water flow through a
  semi permeable membrane that blocks the transport
  of salts or other solutes through it.
• Ex. Water leaving the semi permeable membrane of
  a grape, turning the grape into a raisin.

15

Osmosis and Osmotic Pressure

• If there is only water in the device, the level
  will be the same at both sides of the connected
  vessels separated by a semi permeable membrane.
  When a solution is added to one side, water will
  start to flow into it, so that its level will go
  up at this side, and down at the other side.The
  system will stabilize when the osmotic pressure
  is balanced by the difference in the water levels.

16

Osmosis and Osmotic Pressure

• Uses of Osmosis
• Water Purification
• Desalination
• Waste Material Treatment
• Chemical and Biochemical Laboratory and
  Industrial Processes.

• Uses of Osmotic Pressure
• Chemistry
• Biology
• Pharmacology
• Molecular Medicine
• Calculation of Molar Mass

17

Osmosis and Osmotic Pressure

• Different Osmotic Pressures
• Same osmotic pressure solutions are called
  isotonic.
• Lower osmotic pressure solutions are called
  hypotonic.
• Higher osmotic pressure solutions are called
  hypertonic.