8 8 Partial Pressure Daltons Law Our cells

  • Slides: 16
Download presentation
8. 8 Partial Pressure (Dalton’s Law) Our cells continuously use oxygen and produce carbon

8. 8 Partial Pressure (Dalton’s Law) Our cells continuously use oxygen and produce carbon dioxide. Both gases move in and out of the lungs through the membranes of the alveoli, the tiny air sacs at the ends of the airways in the lungs. Learning Goal Use Dalton’s law of partial pressures to calculate the total pressure of a mixture of gases. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Partial Pressure The partial pressure of a gas is the pressure that each gas

Partial Pressure The partial pressure of a gas is the pressure that each gas in a mixture would exert if it were by itself in the container. Core Chemistry Skill Calculating Partial Pressure General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Dalton’s Law of Partial Pressures Dalton’s law of partial pressures indicates that • pressure

Dalton’s Law of Partial Pressures Dalton’s law of partial pressures indicates that • pressure depends on the total number of gas particles, not on the types of particles. • the total pressure exerted by gases in a mixture is the sum of the partial pressures of those gases. PT = P 1 + P 2 + P 3 +. . General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Total Pressure For example, at STP, 1 mole of a pure gas in a

Total Pressure For example, at STP, 1 mole of a pure gas in a volume of 22. 4 L will exert the same pressure as 1 mole of a gas mixture in 22. 4 L. Gas mixtures 1. 0 mole N 2 1. 0 atm 0. 4 mole O 2 0. 6 mole He 1. 0 mole 1. 0 atm General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake 0. 5 mole O 2 0. 3 mole He 0. 2 mole Ar 1. 0 mole 1. 0 atm © 2016 Pearson Education, Inc.

Total Pressure The air we breathe • is a mixture of different gases. •

Total Pressure The air we breathe • is a mixture of different gases. • contains mostly N 2 and O 2, and contains small amounts of other gases. What we call the atmospheric pressure is actually the sum of the partial pressures of the gases in the air General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Guide to Solving for Partial Pressure General, Organic, and Biological Chemistry: Structures of Life,

Guide to Solving for Partial Pressure General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Solving for Partial Pressure A scuba tank contains O 2 with a pressure of

Solving for Partial Pressure A scuba tank contains O 2 with a pressure of 0. 450 atm and He at 855 mm. Hg. What is the total pressure in mm. Hg in the tank (volume and temperature are constant)? STEP 1 Write the equation for the sum of the partial pressures. Ptotal = PO 2 + PHe STEP 2 Rearrange the equation to solve for the unknown pressure. Convert units to match. Ptotal = PO 2 + PHe General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Solving for Partial Pressure A scuba tank contains O 2 with a pressure of

Solving for Partial Pressure A scuba tank contains O 2 with a pressure of 0. 450 atm and He at 855 mm. Hg. What is the total pressure in mm. Hg in the tank (volume and temperature are constant)? STEP 3 Substitute known pressures and calculate the unknown partial pressure. Ptotal = PO 2 + PHe Ptotal = 342 mm. Hg + 855 mm. Hg = 1. 20 x 103 mm. Hg General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Study Check For a deep dive, a scuba diver uses a mixture of helium

Study Check For a deep dive, a scuba diver uses a mixture of helium and oxygen with a pressure of 8. 00 atm. If the oxygen has a partial pressure of 1280 mm. Hg, what is the partial pressure of the helium (volume and temperature are constant)? A. 520 mm. Hg B. 2040 mm. Hg C. 4800 mm. Hg General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Solution For a deep dive, a scuba diver uses a mixture of helium and

Solution For a deep dive, a scuba diver uses a mixture of helium and oxygen with a pressure of 8. 00 atm. If the oxygen has a partial pressure of 1280 mm. Hg, what is the partial pressure of the helium (volume and temperature are constant)? STEP 1 Write the equation for the sum of the partial pressures. Ptotal = PO 2 + Phe STEP 2 Rearrange the equation to solve for the unknown pressure. Convert units to match. PHe = Ptotal − PO 2 × General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Solution For a deep dive, a scuba diver uses a mixture of helium and

Solution For a deep dive, a scuba diver uses a mixture of helium and oxygen with a pressure of 8. 00 atm. If the oxygen has a partial pressure of 1280 mm. Hg, what is the partial pressure of the helium (volume and temperature are constant)? STEP 3 Substitute known pressures and calculate the unknown partial pressure. PHe = 6080 mm. Hg – 1280 mm. Hg = 4800 mm. Hg or 4. 80 × 103 mm. Hg The answer is C, 4800 mm Hg. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Chemistry Link to Health: Blood Gases • In the lungs, O 2 enters the

Chemistry Link to Health: Blood Gases • In the lungs, O 2 enters the blood, while CO 2 from the blood is released. • In the tissues, O 2 enters the cells, which releases CO 2 into the blood. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Chemistry Link to Health: Blood Gases In the body, • O 2 flows into

Chemistry Link to Health: Blood Gases In the body, • O 2 flows into the tissues because the partial pressure of O 2 is higher in blood and lower in the tissues. • CO 2 flows out of the tissues because the partial pressure of CO 2 is higher in the tissues and lower in blood. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Chemistry Link to Health: Partial Pressures in Blood and Tissue General, Organic, and Biological

Chemistry Link to Health: Partial Pressures in Blood and Tissue General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Gas Exchange During Breathing General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen

Gas Exchange During Breathing General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Concept Map, Gas Laws General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen

Concept Map, Gas Laws General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.