1. PPM (parts per million) PPM = grams solute X 1,000,000 PPM = grams solute X 1,000,000 used when solute is present in very small amounts (The Regents don ’ t follow this rule) used when solute is present in very small amounts (The Regents don ’ t follow this rule) like % except you multiply by 1,000,000 instead of 100 grams solution

2. LET’S PRACTICE: About 0.0043 g of O 2 can be dissolved in 100 mL of water at 20 o C. Express in ppm. [Memorize: 1 mL water has mass of 1 g] What is the solvent? Water How much solvent is there? 100 mL = 100 g How much solute is there? 0.0043g How much is the total solution? 100 g +.0043 g = 100.0043g

3. LET’S PRACTICE: About 0.0043 g of O 2 can be dissolved in 100 mL of water at 20 o C. Express in ppm. THE EQUATION ppm = 0.0043g X 1,000,000 100.0043g ppm = 43 ppm [Memorize: 1 mL water has mass of 1 g]

4. NOW YOU TRY: CO 2 gas has solubility of 0.0972 g/100 g water at 40 o C; Express in parts per million ppm = 0.0972 g solute X 1,000,000 100.0972 g solution = 971 ppm

5. HERE’S ANOTHER: What is the concentration in ppm of a solution with 30.0 g NaNO 3 in 70.0 g water? ppm = 30.0 g NaNO 3 X 1,000,000 100.0 g solution = 300,000 = 3.0 X 10 5 ppm

6. LAST ONE: How many grams of KOH are needed to be dissolved in water to make 2000.0 grams of a 10.0 ppm solution? 10 ppm = X grams KOH X 1,000,000 2000.0 g solution X = 0.02 grams KOH