14.1 The Gas Laws > 1 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Chapter 14 The Behavior of Gases 14.1 Properties of Gases 14.2 The Gas Laws 14.3 Ideal Gases 14.4 Gases: Mixtures and Movements

14.1 The Gas Laws > 2 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Compressibility Compressibility is a measure of how much the volume of matter decreases under pressure.

14.1 The Gas Laws > 3 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Compressibility Do Now: a)How many mm Hg are in 2.50 atm? b)How many kPa are in 2.50 atm? c)How many atm are in 385 mm Hg? d)Convert 100 deg C to Kelvin. e)Convert 73 K to deg C. 1 atm = 760 mm Hg = kPa T Kelvin = T Celsius + 273

14.2 The Gas Laws > 4 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Boyle’s Law P 1  V 1 = P 2  V 2 Boyle’s law For a given mass of gas at constant temperature, the volume of the gas varies inversely with pressure.

14.2 The Gas Laws > 5 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Interpret Graphs As the volume decreases from 1.0 L to 0.5 L, the pressure increases from 100 kPa to 200 kPa.

14.2 The Gas Laws > 6 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Sample Problem 14.1 Using Boyle’s Law A balloon contains 30.0 L of helium gas at 103 kPa. What is the volume of the helium when the balloon rises to an altitude where the pressure is only 25.0 kPa? (Assume that the temperature remains constant.)

14.2 The Gas Laws > 7 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Sample Problem 14.1 KNOWNS P 1 = 103 kPa V 1 = 30.0 L P 2 = 25.0 kPa UNKNOWN V 2 = ? L Analyze List the knowns and the unknown. 1

14.2 The Gas Laws > 8 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Sample Problem 14.1 Rearrange the equation to isolate V 2. Calculate Solve for the unknown. 2 V 2 = P2P2 V1  P1V1  P1 Isolate V 2 by dividing both sides by P 2 : P 1  V 1 = P 2  V 2 P2P2 P2P2

14.2 The Gas Laws > 9 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Sample Problem 14.1 Substitute the known values for P 1, V 1, and P 2 into the equation and solve. Calculate Solve for the unknown. 2 V 2 = 25.0 kPa 30.0 L  103 kPa V 2 = 1.24  10 2 L

14.2 The Gas Laws > 10 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Sample Problem 14.1 A decrease in pressure at constant temperature must correspond to a proportional increase in volume. The calculated result agrees with both kinetic theory and the pressure- volume relationship. The units have canceled correctly. Evaluate Does the result make sense? 3

14.2 The Gas Laws > 11 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. A sample of neon gas occupies a volume of 677 mL at 134 kPa. What is the pressure of the sample if the volume is decreased to 642 mL?

14.2 The Gas Laws > 12 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. A sample of neon gas occupies a volume of 677 mL at 134 kPa. What is the pressure of the sample if the volume is decreased to 642 mL? P 1  V 1 = P 2  V 2 P 2 = V2V2 V1  P1V1  P1 642 mL 677 mL  134 kPa P 2 = 141 kPa

14.2 The Gas Laws > 13 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. A gas occupies 12.3 L at a pressure of 40.0 mm Hg. What is the volume when the pressure is increased to 60.0 mm Hg?

14.2 The Gas Laws > 14 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. A gas occupies 12.3 L at a pressure of 40.0 mm Hg. What is the volume when the pressure is increased to 60.0 mm Hg? 8.2 L

14.1 The Gas Laws > 15 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. END OF 14.2