2. Just add them up! 200 kPa500 kPa400 kPa1100 kPa ++=

3. Dalton’s Law The total pressure of a mixture of gases equals the sum of the partial pressures of the individual gases. P total = P 1 + P 2 +... Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

4. = + + + Dalton’s Law of Partial Pressures & Air Pressure P O2O2 P N2N2 P CO 2 P Ar EARTH P O2O2 P N2N2 P CO 2 P Ar P Total 149 590 3 8 mm Hg P Total = + + + 149 mm Hg 590 mm Hg 3 mm Hg 8 mm Hg P Total = 750 mm Hg

5. Evaporation of Water

6. Vapor Pressure

7. Table of Partial Pressures of Water Vapor Pressure of Water Temperature Pressure ( o C) (kPa) 0 0.6 5 0.9 8 1.1 10 1.2 12 1.4 14 1.6 16 1.8 18 2.1 20 2.3 ( o C) (kPa) 21 2.5 22 2.6 23 2.8 24 3.0 25 3.2 26 3.4 27 3.6 28 3.8 29 4.0 ( o C) (kPa) 30 4.2 35 5.6 40 7.4 50 12.3 60 19.9 70 31.2 80 47.3 90 70.1 100 101.3

8. Collecting Gas By Water Displacement When H 2 gas is collected by water displacement, the gas in the collection bottle is actually a mixture of H 2 and water vapor.