1. Solutions and Colloids
Chemistry B11
Chapter 7
Solutions and Colloids

2. Mixtures
Mixture: is a combination of two or more pure substances.
Homogeneous: uniform and throughout
Air, Salt in water
Solution
Heterogeneous: nonuniform
Soup, Milk, Blood

3. Solutions
Gas in gas (air) solid in solid (alloys) liquid in liquid (alcohol in water)
Gas in liquid (cokes) solid in liquid (sugar in water)
Solutions
Well-mixed (uniform) – single phase
homogenous
transparent
cannot be separated by filtration
cannot be separated on standing
sugar in water

4. Solutions (liquid in liquid)
Solvent: greater quantity (water)
Solute: smaller quantity (sugar)
for liquid in liquid
Immiscible: two liquids do not mix.
miscible: two liquids can mix.
alcohol in water
(in any quantities)

5. Solutions
Saturated: solvent contains or holds all the solute it can (at a given T).
maximum solute that solvent can hold (Equilibrium).
Unsaturated: solvent can hold more solute (at a given T).
Is not the maximum solute that solvent can hold.
Supersaturated: solvent holds more solute that it can normally hold
(at a given T).
(more than an equilibrium condition)

6. Temperature and Solutions
Solubility: the maximum solute that will dissolve in a given amount of a solvent
(at a given T).
T 
Solubility 
T 
Crystal is formed

7. Temperature and Solutions
Solubility 
Supersaturated solution
Seeding
A surface on which to
begin crystallizing.

8. gas in liquid: T ↑
Solubility ↓
Global Warming

9. Pressure and Solutions
Henry’s law
P 
Solubility  (gas in liquid)
More pressure more interactions with the liquid

10. Concentration
Concentration: amount of a solute dissolved in a given quantity of solvent.
1. Percent concentration:
Weight solute (g)
Weight / volume (W / V)% =
× 100
Volume of solution (mL)
Weight solute (g)
Weight / Weight (W / W)% =
× 100
Weight of solution(g)
Volume solute (mL)
Volume / volume (V / V)% =
× 100
Volume of solution (mL)

11. Concentration
2. Molarity (M): number of moles solute dissolved in 1 L of solution.
moles solute (n)
Molarity (M) =
volume of solution (L)
Molarity × V = number of moles (n)
prepare the solution: M, V → n (mol) → m (g)

12. prepare the solution: M, V → n (mol) → m (g)
Preparing a solution
prepare the solution: M, V → n (mol) → m (g)
m (g)
Volumetric flask

13. Concentration 3. Parts per Million (ppm): g solute ppm = × 106
g solvent
Parts per billion (ppb):
g solute
ppb =
× 109
g solvent

14. Concentrated solution
Dilution
Concentrated solution
(Stock solution)
Dilute solution

15. Dilution M1V1 = moles(n) before dilution
M2V2 = moles(n) after dilution
M1V1 = M2V2
M1V1/V2 = M2

16. # of Equivalents in 1 mole
Number of Equivalents (Eq) in 1 mole of each ion is number of charge on that ion.
Ion
Charge
# of Equivalents in 1 mole
Na+ 1+
1 Eq
Ca2+ 2+
2 Eq
Fe3+ 3+
3 Eq
Cl- 1-
SO42- 2-

17. Equivalent
Ex. 1: How many equivalents of CO32- are in 1 mole of Al2(CO3)3?
The charge of CO32- is 2- → 1 mole Al2(CO3)3 has 6 Eq CO32-.
Ex. 2: How many equivalents of Fe3+ are in 5 mole of Fe2O3?
The charge of Fe3+ is 3+ → 1 mole Fe2O3 has 6 Eq.
5 moles: 5 × 6 = 30 Eq

18. Water in our body About 60% mass of our body.
Most of the reactions occur in aqueous solution.
Participates in many biochemical reactions.
Transports reactants and products from one place in our
body to another.
5. Eliminates the waste materials from cells and our body (urine).

19. Solvent and Solute polar dissolves polar like dissolves like
Nonpolar dissolves nonpolar
like dissolves like
Ions Hydrated by H2O
Hydration

20. Solvent and Solute
All nitrates (NO3-) and acetate (CH3COO-) are soluble in water.
Most chlorides (Cl-) and sulfates (SO42-) are soluble in water.
(except AgCl, BaSO4, and …)
Most carbonates (CO32-), phosphates (PO43-) and
hydroxides (OH-) are insoluble in water.
(except NaOH, LiOH, KOH, and NH4OH)

21. Electrolytes + - Electrolyte: conducts an electric current.
bulb + -
electrolyte
Electrolyte: conducts an electric current.
Cl-
Na+
Ionization (Dissociation)
NaCl → Na+ + Cl-
strong electrolytes: molecules dissociate completely into ions (NaCl).
weak electrolytes: molecules dissociate partially into ions (CH3COOH).
nonelectrolytes: molecules do not dissociate into ions (DI water).

22. non transparent, non uniform, large particles, cloudy (milky)
Colloids
Solutions: diameter of the solute particles is under 1 nm (10-9)
Colloids: diameter of the solute particles is between 1 to 1000 nm.
non transparent, non uniform, large particles, cloudy (milky)
but a stable system

23. Colloids Tyndall effect:
You can see the pathway of the light passing
through a colloid. (particles scatter light.)
emulsion: a mixture of immiscible substances (liquid-liquid).
(milk and mayonnaise)

24. suspension: system does not stay stable and settles (> 1000 nm).
(sand in water)

25. Brownian motion Random motion of colloid particles. Dust
Why do colloidal particles remain in solution and do not stick together?
1. Surrounding water molecules prevent colloidal molecules
from touching and sticking together.
2. A charged colloidal particle encounters another particle
of the same charge, they repel each other.

26. Freezing and boiling point
If we dissolve a solute in a solvent:
bp  fp 
ΔT: change of bp or fp (T2 - T1)
i: number of particles
K: constant (depend on solute) – Kb Kf
M: molarity
ΔT = ikM
NaCl  Na+ + Cl-
i = 2
K2SO4  2K+ + SO42-
i = 3
C2H6O (Ethanol)
i = 1

27. Osmotic Pressure Semipermeable membrane osmotic pressure
Higher concentration → Higher osmotic pressure

28. Osmotic Pressure Water flows from low concentration to
high concentration.

29. Osmotic Pressure Osmolarity (osmol) = M × i M: molarity
i: number of particles
Osmolarity ↑ → Osmotic pressure ↑

30. Hemolysis Crenation Isotonic solution Hypotonic solution
Hypertonic solution
Equal Water in Water out
Hemolysis
Crenation

31. The most typical isotonic solutions
0.9% (m/v) NaCl
5% (m/v) Glucose
0.9 g NaCl/100 mL of solution
5 g glucose/100 mL of solution
Higher than these numbers → Hypertonic solution
Lower than these numbers → Hypotonic solution

32. Dialysis
Dilute solution