1. Solutions!

2. Classification of Matter
Pure
Substances
Mixtures
Homogeneous
Heterogeneous
Elements
Compounds

3. Mixtures homogeneous: heterogeneous: will not separate small particles
evenly distributed
too small to be seen
can’t be sorted or trapped by filter
won’t scatter light
settles upon standing
variable particle sizes
uneven distribution
visibly different regions
can be separated depending on particle sizes
scatters light

4. Solution
homogeneous mixture of 2 or more substances in a single physical state (phase)

5. Parts of a Solution solute = substance being dissolved
solvent = dispersing medium
substance being dissolved into

6. Can you identify the solute and solvent in each picture?

7. solute = ? solvent = ?

8. hints to identify solute & solvent
substance that changes phase
substance that have less of
solvent:
substance that maintains phase
substance that have more of

9. Aqueous Solutions water is solvent
transition metals form brightly colored solutions

10. solutions occur in all 3 phases
solute
solvent
example
gas
air
liquid
water vapor in air
solid
SO2(s) in air - smog
CO2(g) in water (soda)
antifreeze(l) in water in car radiator
salt water
H2(g) in palladium metal
dental amalagum fillings: Hg (l) in Au(s)/Ag(s)
alloys: Brass, etc.

11. gas in a liquid: CO2 in and out of water
bubbles mean it’s a mixture not a solution!

12. Concentration of Solutions

13. Concentration measurement that describes
how much solute in given amount of
solvent or solution
express concentration using many, many different units
pick the unit according to task at hand

14. Percent
by mass OR
by volume
% = part x
whole

15. Twists in Word Problems
sometimes ask for part or whole, not percent
sometimes give volume/mass of solution
sometimes give volume/mass of solvent and volume/mass of solute
mass solution = mass solute + mass solvent

17. ppm (parts per million)
used when solute is present in very small amounts
(Regents board doesn’t quite follow this rule)

18. ppm (parts per million)
ppm = grams solute x 1,000,000
ppm is ratio between mass solute & mass soln
similar to % except the whole is 1,000,000 instead of 100
grams solution

19. About 0. 0043 g of O2 can be dissolved in 100 mL of water at 20oC
About g of O2 can be dissolved in 100 mL of water at 20oC. Express in ppm.
[memorize: 1 mL water has mass of 1 g]
ppm = g x 1,000,000 g
= 43 ppm

20. CO2 gas has solubility of 0. 0972 g/100 g water at 40oC
CO2 gas has solubility of g/100 g water at 40oC. Express in parts per million.
ppm = g solute x 1,000,000
g solution
= 971 ppm

21. What is the concentration in ppm of a solution with 30.0 g NaNO3 in 70.0 g water?
ppm = g NaNO x ,000,000
100.0 g solution
= 300,000 = 3.0 X 105 ppm

22. How many grams of KOH are needed to be dissolved in water to make 2000
How many grams of KOH are needed to be dissolved in water to make grams of a 10.0 ppm solution?
10 ppm = ? grams KOH X 1,000,000
g solution
? = 0.02 grams KOH