Solution%20Chemistry

1
Solution Chemistry

• Packet 4
• Chapter 13
• Sections 1 3

2
Introduction

• Solutions are homogenous (everywhere the same)
  mixtures of substances that combine to form a
  single phase (generally liquid).
• Recall that a mixture is a physical blend of two
  or more substances.
• Mixtures may not be always a liquid
• Example
• Smoke in air

3
Solutions vs. Suspensions

• A suspension is a temporary heterogeneous
  mixture.
• A type of mixture in which the different parts
  spontaneously separate over time.
• Clay and water
• Over time, the clay eventually settles to the
  bottom.

4
Solutions vs. Suspensions

• Solutions stay uniform over time and the
  substances do not separate.

5
Parts of a Solution
6
Parts of a Solution

• There are two general parts of a solution
• Solvent
• The primary ingredient
• Present in large amounts
• Solute
• The other ingredients found in much smaller
  portions

7
The Water Connection

• Water is the most common solvent.
• Furthermore, any solution that contains water, as
  the solvent, is an aqueous solution.

8
Colloids
9
Introduction

• Colloids are stable heterogeneous mixtures that
  resemble homogenous mixtures.
• Colloid is derived from a Greek word meaning
  glue-like.
• Milk is a colloid that contains globules of fat
  and small lumps of protein casein.
• Mayonnaise is a colloid that contains water
  droplets in oil.

10
Separation of Mixtures
11
Separation of Mixtures

• There are multiple ways of separating mixtures.

12
Separation of Mixtures II

• Separation of Mixtures at Home
• Using a filter to make coffee
• Evaporation that occurs when cooking
• Leading to the burning of ones food

13
Separation of Mixtures III

• Separating Mixtures in a Lab
• Centrifugation
• The use of a centrifuge, spinning up to 80,000
  revolutions per minute and increasing the force
  of gravity up to times what is seen on earth,
  can separate substances found in mixtures based
  upon the different sizes of the molecules.

14
Separation of Mixtures IV

• Chromatography
• Separation is based on how quickly the components
  in the mixture is dissolved in a mobile phase
  solvent.
• Paper chromatography is is a useful technique for
  separating components of a solution.

15
Separation of Mixtures V

• Distillation
• Separates components based on the boiling points
• One component reaches its boiling point faster
  than the other(s).
• Is this how salt is obtained from the ocean?

16
Solubility
17
Definition

• The solubility of a substance is the maximum
  amount of that substance that can be dissolved in
  a particular solvent at a particular temperature.

18
Solubility II

• Glucose, a type of sugar, will dissolve in 100ml
  of H2O until a maximum amount has been added
  (83g)
• Once the maximum has been achieved, the solution
  is said to be in equilibrium and is saturated.

19
Solubility III

• A solution that is below the saturation point is
  described as undersaturated solution.
• A solution that is above the saturation point,
  where added substance precipitates at the bottom
  is described as a supersaturated solution.
• Concentrated Solution.

20
Dissolving Gases in Liquids
21
The Soda Bottle

• CO2 resides above the liquid before the bottle is
  opened and is in equilibrium with the gas in the
  liquid.
• The solution is at the point of saturation.
• When the bottle is opened, the CO2 is no longer
  in equilibrium with the CO2 in the air and
  escapes the bottle/liquid in an attempt to reach
  that equilibrium point.

22
The Soda Bottle II

• Henrys Law
• At a constant temperature, the solubility of a
  gas in a liquid is directly proportional to the
  partial pressure of the gas on the surface of the
  liquid.