1. GASES

2. 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.”

3. 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

4. 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 = 101.3 kPa 5.1

5. 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

6. 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 + 273 0 K is called absolute zero 5.2

7. Figure 5.17 The Effects of Increasing the Temperature of a Sample of Gas at Constant Pressure

8. 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

9. As Pressure Increases, the Volume of SO 2 Decreases

10. As Pressure Increases, the Volume Decreases

11. 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

12. Figure 5.18 Increased Volume due to Increased Moles of Gas at Constant Temperature and Pressure

13. 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

14. 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 = 0.08206 L·atm/mol·K) 5.3

15. 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