• Explain which factors can affect solubility of solids, liquids and gases.

 Include: pressure and temperature • Differentiate among saturated, unsaturated,

and supersaturated solutions. • Use a graph of solubility data to solve problems.

Additional KEY Terms

Factors that affect Solubility

1. Nature of the Solvent and Solute

**The general dissolving rule is like dissolves like.**

Polar Solvent Non-polar Solvent

Polar Solute

Ionic Solute

Non-Polar Solute

2. Surface area (crushing)• Dissolves faster with increased surface area Amount dissolved depends on level of attraction

3. Agitate (stir) the mixture• Added energy of stirring dissolves it faster Added energy can help more particles dissolve

4. Temperature

HOT

• Temperature increases the solubility of solids in a solvent. (endothermic processes)

H

O

H

-+

H

O

H

H H

H

H

C C

+-

H

O

H

H H

H

H

C C

+-

H

O

H

H H

H

H

C C

+-

H

O

H

H H

H

H

C C

+-

H

O

H

H H

H

H

C C

+-

H

O

H

-+ H

O

H

-+

H

O

H

-+H

O

H

-+

H

O

H

-+

Adding heat supplies more energy to separate the solute and solvent particles.

BUT… Increasing temperature decreases solubility of gases in a solvent.

FLATAs kinetic energy of dissolved gas particles increases,

particles overcome attractive forces and escape.

5. Pressure (only affects gases)

Pressure increases the solubility of gas in a solvent.

• Forces gas particles into contact with the liquid

• weak attraction

Anything that adds energy to the dissolved gas particles, gives them energy to escape attraction

Types Of Solutions

1. Saturated solution • MAX amount dissolved at that temperature if you add more solute, it will not dissolve

2. Unsaturated • Solvent is able to dissolve more at that temp

2. Supersaturated • Solvent is holding more solute than normally

can at that temperature

• A supersaturated solution is very unstable.

Heat

bump, add crystal, shake

Solubility• amount of solute needed to make a saturated

solution (under given conditions) Units - grams of solute per 100 grams of solvent.

- grams of solute per 100 mL of solvent.

• Dependent on temperature.• Proportional to volume of solvent

Solubility of a solute is determined experimentally and is shown with a “solubility curve”

You can solve this problem by using ratios.

30 g = g 250 mL 500 mL

(500 mL)(500 mL) 60

30 g

250 mL 500 mL

If a maximum of 25.0 g of solute can dissolve in 40.0 g of solvent, what is the solubility in 100 g of solvent at the same temperature?

You can solve this problem by using ratios.

grams of solute1 = grams of solute2

grams of solvent1 grams of solvent2

25.0 g1 = g2

40.0 g1 100 g2

(100 g2)(100 g2)62.5

If 30.1 g of a solute dissolves in 350.0 mL of water at a certain temperature, what is the solubility of the substance in g/100g water?

grams of solute1 = grams of solute2

grams of solvent1 grams of solvent2

30.1 g1 = g2

350.0 g1 100 g2

(100 g2)(100 g2)8.60

Density of water is 1 g/1 mL So # mL = # grams

What volume of water is required to dissolve 240 g of KNO3 at 60°C?

=

240 g2212 mL2 ? mL2

grams of solute1 = grams of solute2

mL of solvent1 mL of solvent2100 mL1

113 g1

=

240 g2

? mL2100 mL1

113 g1

75 mL of a saturated solution of KNO3 at 70°C is cooled to 40°C. How much solid precipitates from the solution?

105 g – 49.5 g = 55.5 g

? g2 =

75.0 mL2100 mL1

140 g1 ? g2 =

75.0 mL2100 mL1

65 g1 105 g2 49.6 g2

CAN YOU / HAVE YOU?

• Explain which factors can affect solubility of solids, liquids and gases.

 Include: pressure and temperature • Differentiate among saturated, unsaturated,

and supersaturated solutions. • Use a graph of solubility data to solve problems.

Additional KEY Terms