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Partial Pressures. Dalton’s Law of Partial Pressures & Air Pressure. 8 mm Hg. P. 590 mm Hg. Ar. P. P. P. P. P. N 2. P. = + + +. Total. O 2. N 2. CO 2. Ar. 149 mm Hg. P. P. O 2.
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Dalton’s Law of Partial Pressures & Air Pressure 8 mm Hg P 590 mm Hg Ar P P P P P N2 P = + + + Total O2 N2 CO2 Ar 149 mm Hg P P O2 149 590 3 8 mm Hg = + + + Total 3 mm Hg P CO2 PTotal = 750 mm Hg EARTH
Dalton’s Partial Pressures Zumdahl, Zumdahl, DeCoste, World of Chemistry2002, page 421
Dalton’s Law Zumdahl, Zumdahl, DeCoste, World of Chemistry2002, page 422
Dalton’s Law Applied Suppose you are given four containers – three filled with noble gases. The first 1 L container is filled with argon and exerts a pressure of 2 atm. The second 3 liter container is filled with krypton and has a pressure of 380 mm Hg. The third 0.5 L container is filled with xenon and has a pressure of 607.8 kPa. If all these gases were transferred into an empty 2 L container…what would be the pressure in the “new” container? PKr = 380 mm Hg Ptotal = ? PAr = 2 atm Pxe 607.8 kPa V = 1 liter V = 3 liters V = 0.5 liter V = 2 liters
…just add them up PKr = 380 mm Hg Ptotal = ? PAr = 2 atm Pxe 607.8 kPa V = 1 liter V = 3 liters V = 0.5 liter V = 2 liters Dalton’s Law of Partial Pressures “Total Pressure = Sum of the Partial Pressures” PT = PAr + PKr + PXe + … P1 x V1 = P2 x V2 P1 x V1 = P2 x V2 (0.5 atm) (3L) = (X atm) (2L) (6 atm) (0.5 L) = (X atm) (2L) PKr = 0.75 atm Pxe = 1.5 atm PT = 1 atm + 0.75 atm + 1.5 atm PT = 3.25 atm
Same Gas, Volume, and Temperature, but… Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 316
Same Gas, Volume, and Temperature, but…different numbers of moles Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 316