• Slides: 25

A skydiver leaps into the earth's atmosphere, which is composed of a mixture of gases. Source: Brian Erler/Taxi/Getty Images Copyright © Houghton Mifflin Company. All rights reserved. 2

Steve Fossett flies his balloon Solo Spirit, over the east coast of Australia during his attempt to make the first solo balloon flight around the world. Source: AP Photo/Steve Holland

Figure 12. 1: The pressure exerted by the gases in the atmosphere can be demonstrated by boiling water in a can. Copyright © Houghton Mifflin Company. All rights reserved. 4

Figure 12. 2: When a glass tube is filled with mercury and inverted in a dish of mercury at sea level, the mercury flows out of the tube until a column approximately 760 mm high remains.

Checking the air pressure in a tire.

Figure 12. 4: A J-tube similar to the one used by Boyle.

Figure 12. 5: A plot of P versus V from Boyle’s data in Table 12. 1.

Figure 12. 7: Plots of V (L) versus T (°C) for several gases.

Figure 12. 8: Plots of V versus T as in Figure 12. 7, except that here the Kelvin scale is used for temperature.

The air in a balloon expands when it is heated. This means that some of the air escapes from the balloon, lowering the air density inside and thus making the balloon buoyant. Source: John A. Rizzo/ Photo. Disc/Getty Images

Figure 12. 9: The relationship between volume V and number of moles n. As the number of moles is increased from 1 to 2 (a to b), the volume doubles. Copyright © Houghton Mifflin Company. All rights reserved. 17

Popcorn popping.

Figure 12. 10: When two gases are present, the total pressure is the sum of the partial pressures of the gases. Copyright © Houghton Mifflin Company. All rights reserved. 19

Figure 12. 11: The total pressure of a mixture of gases depends on the number of moles of gas particles (atoms or molecules) present, not on the identities of the particles. Copyright © Houghton Mifflin Company. All rights reserved. 20