# Is there a LIMIT to how much solute can dissolve into the solvent?

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Is there a LIMIT to how much solute can dissolve into the solvent?

Solutions Homogeneous Mixtures

Solution : Solvent: substance present in a
Greater (Larger) amount Solute: substance that is present in a lesser (Smaller) amount

“Likes dissolve likes”
Polar dissolves in polar Sugar and water Nonpolar dissolves in non polar crayons and oil

Molarity (M or mol/L) CONCENTRATION
Mole fraction ( c or mol/ mol total) Molality (m or mol/Kg solvent) Mass percent (% or g/ g total)

Solutions can be classified as saturated or unsaturated.
Definitions Solutions can be classified as saturated or unsaturated. A saturated solution contains the maximum quantity of solute that dissolves at that temperature.

Solvation: The attaching of solvent particles to solute particles.
Solvation Process D6 c20 Solvation: The attaching of solvent particles to solute particles.

Solubility: Maximum amount of solute
SATURATED SOLUTIONS Solubility: Maximum amount of solute per 100 g solvent

Dissolving Effects: c34 Saturated Solution- maximum amount of solute in solution Any extra solute added just sits on bottom. Unsaturated- less than max. solute than then can be dissolve. Supersaturated- A solution containing more solute than normal for a given temperature. Must heat a saturated solution up. Then return it to room temperature.

For a Supersaturated solution, when more solute is
added, the extra solute will settle to the bottom

Supersaturated Sodium Acetate
One application of a supersaturated solution is the sodium acetate “heat pack.” Sodium acetate has an ENDOthermic heat of solution.

Temperature effects the solubility of a substance

Solubility Curves How much LiCl will dissolve into 100 ml of water at a temperature of 20 C? How much KCl will dissolve into 500 ml of water at a temperature of 80 C? How much RbCl will fall out of solution if 200 ml of solution is cooled from a temperature of 80 C to 20 C?

Dissolving Effects Solubility- the quantity of solute that will dissolve in 100 g of solvent at a set temperature If solution is holding the MAX. Amount of solute called saturated Solid ionic compounds: more in with higher temperature Gases: More in at lower temperatures

SOLIDS GAS

Dissolving Gases & Pressure
Gas solubility can be changed by both the temperature and PRESSURE. When the can of soda is opened the pressure (Pgas) drops and causes the solubility to decrease.

Henry’s Law Gas solubility (mol/L) = Sg Sg = kH • Pgas
kH = Henry’s law constants for O2 = x 10-6 M/mmHg When Pgas increases, solubility increases.

Henry’s Law Sg = kH • Pgas kH for O2 = 1.66 x 10-6 M/mmHg
What is the concentration of oxygen in fresh water when the air pressure is 1 atm? Sg = kH • Pgas kH for O2 = x 10-6 M/mmHg O2 = 21% so 0.21(760 torr) = Pgas Sg = 1.66 x 10-6 M/mmHg • 160 torr = 2.66 x 10-4 M What is the concentration of oxygen in milligrams/ liter? O2 = 8.5 mg/L

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