GASES
Copyright © Houghton Mifflin Company. All rights reserved.Chapter 5 | Slide 2 Why study gases? An understanding of real world phenomena. An understanding of how science “works.”
Copyright © Houghton Mifflin Company. All rights reserved.Chapter 5 | Slide 3 A Gas Uniformly fills any container. Mixes completely with any other gas. Exerts pressure on its surroundings. 5.1
Copyright © Houghton Mifflin Company. All rights reserved.Chapter 5 | Slide 4 Pressure Equal to force/unit area SI units = Newton/meter 2 = 1 Pascal (Pa) 1 standard atmosphere = 101,325 Pa 1 standard atmosphere = 1 atm = 760 mm Hg = 760 torr = kPa 5.1
Copyright © Houghton Mifflin Company. All rights reserved.Chapter 5 | Slide 5 Volume and Temperature What law results from observations like these? The volume of a gas depends on the temperature of the gas (constant P and n). 5.2
Copyright © Houghton Mifflin Company. All rights reserved.Chapter 5 | Slide 6 Charles’s Law Volume and Temperature (in Kelvin) are directly related (constant P and n). Charles’s Law: V=bT K = °C K is called absolute zero 5.2
Figure 5.17 The Effects of Increasing the Temperature of a Sample of Gas at Constant Pressure
Copyright © Houghton Mifflin Company. All rights reserved.Chapter 5 | Slide 8 Other Laws Pressure and Volume are inversely related (constant T and n) Boyle’s Law: PV = k 5.2
As Pressure Increases, the Volume of SO 2 Decreases
As Pressure Increases, the Volume Decreases
Copyright © Houghton Mifflin Company. All rights reserved.Chapter 5 | Slide 11 Other Laws Volume and number of moles are directly related (constant T and P) Avogadro’s Law: V = an 5.2
Figure 5.18 Increased Volume due to Increased Moles of Gas at Constant Temperature and Pressure
Copyright © Houghton Mifflin Company. All rights reserved.Chapter 5 | Slide 13 Ideal Gas Law We can bring all of these laws together into one comprehensive law: V = bT PV = k V = an 5.3
Copyright © Houghton Mifflin Company. All rights reserved.Chapter 5 | Slide 14 Ideal Gas Law We can bring all of these laws together into one comprehensive law: PV = nRT (where R = L·atm/mol·K) 5.3
Copyright © Houghton Mifflin Company. All rights reserved.Chapter 5 | Slide 15 p is the absolute pressure of the gas,pressure V is the volume of the gas,volume n is the number of moles of gas,moles R is the universal gas constant,universal gas constant T is the absolute temperature.absolute temperature