Solubility

SATURATED SOLUTION

no more solute dissolves

UNSATURATED SOLUTIONmore solute

dissolves

SUPERSATURATED SOLUTION

becomes unstable, crystals form

increasing concentration

Solubility Table

LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World , 1996, page 517

0 10 20 30 40 50 60 70 80 90 100

Solubility vs. Temperature for Solids

Sol

ubili

ty (g

ram

s of

sol

ute/

100

g H

2O)

KI

KCl

20

10

30

40

50

60

70

80

90

110

120

130

140

100

NaNO3

KNO3

HCl NH4Cl

NH3

NaCl KClO3

SO2

shows the dependence of solubility on temperature

gases

solids

Solubility

SolubilitySolubility

maximum grams of solute that will dissolve

in 100 g of solvent at a given temperature

varies with temperature

based on a saturated solution

Solubility

• Solids are more soluble at...Solids are more soluble at...– high temperatures.

• Gases are more soluble at...Gases are more soluble at...– low temperatures &– high pressures (Henry’s Law).– EX: nitrogen narcosis, the “bends,” soda

Temp. (oC)

Solubility(g/100 g H2O)

KNO3 (s)

KCl (s)

HCl (g)

SOLUBILITYCURVE

Solubility how much solute dissolves in a given amt.

of solvent at a given temp.

unsaturated: solution could hold more solute; belowbelow line

saturated: solution has “just right” amt. of solute; onon line

supersaturated: solution has “too much” solute dissolved in it;

above the line

To

Sol.

To

Sol.

Solids dissolved in liquids Gases dissolved in liquids

As To , solubility As To , solubility

per100 gH2O

Classify as unsaturated, saturated, or supersaturated.

80 g NaNO3 @ 30oC unsaturated

45 g KCl @ 60oC saturated

50 g NH3 @ 10oC unsaturated

70 g NH4Cl @ 70oC supersaturated

So sat. pt. @ 40oC for 500 g H2O = 5 x 66 g = 330 g

120 g < 330 g unsaturated

saturation point @ 40oC for 100 g H2O = 66 g KNO3

Per 500 g H2O, 120 g KNO3 @ 40oC

(A) Per 100 g H2O, 100 g Unsaturated; all solute

NaNO3 @ 50oC. dissolves; clear solution.

(B) Cool solution (A) very Supersaturated; extraslowly to 10oC. solute remains in solution;

still clear.

Describe each situation below.

(C) Quench solution (A) in Saturated; extra solute an ice bath to 10oC. (20 g) can’t remain in

solution, becomes visible.

Hotpack / Coldpack

Solubility of Sodium Acetate

Temperature (oC)

025 50 75 100

Sol

ubili

ty(g

/100

g H

2O)

50

100

150Supersaturated

solution

Unsaturated solution

Saturated

Video Clip

Charles H.Corwin, Introductory Chemistry 2005, page 378

A single crystal of sodium acetate, NaC2H3O2, is dropped into a

supersatureated solution

The small crystal causes extensivecrystallization, and eventually

the solute forms a solid mass of NaC2H3O2.

Vitamins

• Multi Vitamin– Provides many essential

vitamins– “Expensive urine”

• Water Soluble– Vitamin C– Must be replenished regularly

• Fat Soluble– Can overdose – Vitamin A– Can be ingested periodically,

stored in body fat

Gas, Liquid, and Solid

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 441