1. Mixtures

2. Two types Heterogeneous mixtures:
- at least 2 substances that can be seen with naked eye
Ex. Granite rock – can see different coloured minerals

3. Homogeneous mixtures
- mixture with at least 2 substances that cannot be seen with naked eye.
ex. Colloids and solutions

4. Colloids:
homogeneous mixture in which two substances can be distinguished under
a magnifying instrument. Ex. Blood, Milk
naked eye Under microscope

5. Solutions - homogeneous mixture
- impossible to distinguish constituent parts (not even with microscope)
- one visible phase, Translucent? Transparent?
- phase of solution determined by the solvent (see table 1.15, page 13)

6. Dissolution
- when a solution is made the solute is dissolved by the solvent.
- Solute: substance that dissolves in another substance
Solvent: substance that can dissolve a solute
Ex. Salt water(solution): salt (solute), water (solvent)
Human Body: Lymph (solution): waste (solute), water (solvent)
Tears (solution): salt (solute), water (solvent)
Urine (solution): salts, wastes (solutes), water (solvent)

7. Making a solution
Dissolution
Particle Model

8. Particle Model-Dissolution
- solute appears to disappear
- bonds between the solute molecules break
- solute dissolves between the particles of the solvent
- solute becomes microscopic.

9. Concentration
Quantity of dissolved solute in a given quantity of solution.
Units: g/ L % m/V % V/V % m/m
Formula: C = m_ V
C= concentration(g/L) m= mass solute (g) V= volume solution (L)

10. Example 1:
Kenny makes a 50 L solution by dissolving a 100 g of salt in water. What is the concentration of the solution?
C = m/V means “mass ÷ volume”
C= 100 g/ 50 L
C= 2 g/L

11. Example 2:
Kelsey makes a 2 g/L with a volume of 500 mL. How much solute did she use?
Covert mL to L :500 mL ÷ 1000 = 0.5 L
C= m/V
2 = m
0.5
m= 2 (0.5) = 1 g/L

12. Example 3:
Chris buys a 650 ml bottle of contact lens saline (salt water) solution with a concentration of 3%.
How much salt is in the solution?
Convert % to g over 100 mL: 3% = 3 g per 100 mL
3_ = m_
now cross-multiply!
100 m = 3 (650)
100 m = 1950
m = 1950 ÷100 = 19.5 g

13. Changing the concentration of a solution
Dilution – adding solvent to decrease concentration
Concentrate – add solute
Use this formula (C1V1=C2V2) to find the concentration of a diluted solution.

14. Example
2.5g of salt were dissolved in 1L of water. The solution was then diluted by adding 3L of water. What is the concentration of the new solution?

15. Solubility
Refers to the maximum amount of solute that can be dissolved in a given amount of solvent. When a solution is supersaturated, the surplus solute appears as a precipitate. Solubility is affected by the nature of the substance and temperature.

16. What is the solubility of NaCl
at 900C?
At what temperature is the solubility of KNO3 about
87 g/100 g?
What would a solution be called if 125 g of NaNO3 were dissolved at 800C
If the solution in number 3 was cooled to 500C, how much precipitate would form?