CH' 23 Solutions

1
CH. 23 - Solutions

• What are some examples of solutions?
• Pop, milk, lemonade - liquids
• air - gases
• bronze, steel - solids
• The 3 types of solutions - solid, liquid, gas
• A solution is formed when one substance is
  dissolved in another.

2

• A gaseous solution is 2 or more gases mixed
  together.
• A liquid solution occurs when a gas, liquid, or
  solid combines with a liquid.
• A solid solution occurs when a solid or a liquid
  mixes with a solid.
• The substance being dissolved is the solute. Ex.
  Salt in water

3

• The substance that dissolves the solute is the
  solvent. Ex. Water dissolving sugar.
• What might speed up the rate at which the solute
  is dissolved?
• 1. Stir it.
• 2. Crush or grind the solute more.
• 3. Increase the temperature of the solvent.
• Do these factors apply to a gas? Why?

4

• A bottle of pop will release more gases when
  shaken or stirred. Why?
• There are more gas molecules moving around and
  being exposed to the surface.
• A bottle of warm pop will release more gases than
  a cool pop. Why?
• The gas molecules are moving faster and exposed
  more frequently.

5

• What is the most abundant solution in the world?
  E.C.
• Salt water
• So how might we be able to use the salt water?
• Desalination
• There are more than 1500 desalination plants in
  the world, which produces up to 2 billion gallons
  of fresh water each day.

6

• Distillation is another process done by boiling
  water from a solution, then cooling and
  condensing it to collect as fresh water
• What is solubility?
• The maximum number of grams of the substance that
  will dissolve in 100g of the solvent at a certain
  temperature.
• Certain substances dissolve easily. Why?

7

• What is a concentrated solution?
• This is one in which there is a large amount of
  solute in the solvent. Ex. Orange juice
• What is a solution called that is not very
  concentrated?
• Dilute - Ex. Dilute HCl
• What is a saturated solution?
• This is a solution that has dissolved all the
  solute it can hold at a given temperature.

8

• Example of a saturated solution would be adding
  salt to water at 20 degrees C until it no longer
  dissolves.
• So, what is a unsaturated solution?
• It is any solution that can dissolve more solute
  at a given temperature.
• Supersaturated solution contains more solute than
  the solvent can hold.

9

• What is a solvent?
• Dissolves a substance when in contact.
• What is a solute?
• The substance being dissolved.
• Why do some solutes dissolve in some solvents,
  but not in others? E.C.
• polar solvents dissolve polar solutes and
  nonpolar solvents dissolve nonpolar solutes.

10

• Example - water (polar) dissolves salt (polar).
• What happens when a polar molecule, like NaCl,
  gets separated by a polar solvent, like water?
• This is called dissociation
• Now the Na and Cl- molecules separate out from
  the water to form ions.

11

• When the two separate this is called ionization.
  They become ions.
• Any substance that separates into ions or forms
  ions in a water solution is an electrolyte.
• Electrolytes are solutions that can conduct
  electricity.
• Nonelectrolytes do not conduct electricity.

12

• Where do you use antifreeze?
• In the radiator of your car.
• What does it do?
• It increases the boiling point and increases the
  freezing point of the water in your cars
  radiator.
• How does it increase the freezing point?
• It breaks up the regular pattern in which water
  freezes.

13

• Water freezes in a crystal pattern antifreeze
  interferes with that pattern, so it takes a much
  lower freezing point to freeze the water.
• How does antifreeze increase the boiling point?
• It interferes with the evaporation of water, so
  it takes a much higher boiling point.

14

• Salt even helps increase the boiling point of
  water with the same principle.
• If you add antifreeze to your radiator and spill
  some be sure to clean it up. Why?
• Cats and dogs may lick it up it tastes sweet to
  them.