1. Concentration of Solutions

2. Concentration
measurement that describes how much solute is in given amount of solvent or solution
Many, many different units to express concentration - Pick the unit by the task at hand

3. Percent
By mass
By Volume
% = Part x %
Whole

4. Twists 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

5. PPM (parts per million)
PPM = grams solute X 1,000,000
used when solute is present in very small amounts
(The Regents don’t follow this rule)
grams solution

6. PPM (parts per million)
PPM = grams solute X 1,000,000
ppm is ratio between mass solute & mass solution
like % except you multiply by 1,000,000 instead of 100
grams solution

7. 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
ppm = 43 ppm

8. CO2 gas has solubility of 0
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

9. What is the concentration in ppm of a solution with 30.0 g NaNO3 in 70.0 g water?
ppm = g NaNO3 X 1,000,000
100.0 g solution
= 300,000 = 3.0 X 105 ppm

10. 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