1. solution

3. COMPONENTS OF A SOLUTION
SOLUTE – substance being dissolved; present in lower proportion
SOLVENT – the dissolving medium; present in greater proportion

4. TYPES OF SOLUTIONS SOLUTE SOLVENT EXAMPLE GAS O2 in N2 (air) LIQUID
CO2 in soda
SOLID
H2 in palladium
H2O(g) in air
Alcohol in H2O
Hg in Ag
(dental amalgam)
Sugar solution
Steel (C in Fe)

5. SOLVATION – dissolving of solids accompanied by heat of solution
ENDOTHERMIC – dissolution process absorbs heat from the surrounding
EXOTHERMIC – dissolution process releases heat into the surrounding

6. FACTORS AFFECTING SOLUBILITY
1. Nature of solute and solvent – the solute-solvent interaction must be greater than the solute-solute interactions and solvent –solvent interactions (or like dissolves like – polar solutes combine with polar solvent; non-polar solutes combine with non-polar solvents

7. 2. Pressure – The greater the pressure above a liquid, the greater is the solubility of the gas in the liquid.
3. Temperature – The lower the temperature of a liquid, the greater is the solubility of the gas in the liquid.

8. RELATIVE (or comparative) WAYS OF EXPRESSING CONCENTRATION
UNSATURATED or DILUTE – contains a relatively small amount of solute
SATURATED – contains the maximum amount of solute in that a given quantity of solvent can dissolve in a given temperature
SUPERSATURATED – contains more solute than saturated solutions
- prepared by adding more solute to a saturated solution at a higher temperature

9. QUANTITATIVE WAYS OF EXPRESSING CONCENTRATION
PERCENTAGE COMPOSITION
PARTS PER MILLION
MOLE FRACTION
MOLARITY
MOLALITY

10. PERCENTAGE CONCENTRATION
% by mass of solute =
mass of solute X %
mass of solution
% by mass of solvent
mass of solvent X %
% by volume of solute
volume of solute X %
volume of solution
% by volume of solvent
volume of solvent X %

11. (Ex.) What is the % by mass of sugar prepared by dissolving 18 g of sugar in 54 g of water?
Solution:
Mass of solute (sugar) = 18 g
Total mass of solution = mass of sugar + mass of H2O
= 18 g + 54 g = 72 g
% sugar (by mass) = mass of sugar X 100%
mass of solution
= 18 g X 100% = 25 %
72 g

12. PARTS PER MILLION (ppm)
ppm of solute =
mass of solute X
mass of solution
ppm of solvent
mass of solvent X

13. MOLARITY (M) – number of moles (n) of solute per liter of solution (V)

14. Ex. A solution is prepared by dissolving 12 g of NaOH in water to make 80 mL of solution. What is the molarity of the solution?
Solution: Molar Mass (MM) of NaOH
= ( ) g
= 40 g/mole
Number of moles (n) = Given Weight (GW)
Molar Mass (MM)
= g = 0.3 mole
40 g/mole
Molarity (M) = 0.3 mole = 3.75 mole = 3.75 M
0.08 L L

15. MOLALITY (m) – number of moles (n) of solute kilogram of solvent (kg)

16. Ex. What is the molality of a solution if 196 g of H2SO4 is dissolved in 500 grams of water?
Solution: Molar Mass of H2SO4
= 2(1)g + 1(32)g + 4(16)g = 98 g/mole
Number of moles (n) = Given Weight (GW)
Molar Mass (MM)
= g = 2 moles
98 g/mole
m = 2 moles = 4 m
0.5 kg

17. MOLE FRACTION (mf) – number of moles of solute OR solvent divided by the total number of moles in the solution

18. Solution: Molar Mass of H2SO4 = 2(1)g + 1(32)g + 4(16)g = 98 g/mole
Ex. What is the mole fraction of the solute if 196 g of H2SO4 is dissolved in 500 grams of water?
Solution: Molar Mass of H2SO4
= 2(1)g + 1(32)g + 4(16)g = 98 g/mole
Number of moles (n) = Given Weight (GW)
Molar Mass (MM)
H2SO4 = g = 2 moles H2SO4
98 g/mole
H2O = g = 27.8 moles H2O
18 g/mole
mf H2SO4 = 2 moles H2SO4 = 0.067
2 moles H2SO moles H2O