13.1 The Nature of Gases > 1 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Chapter 13 States of Matter 13.1 The Nature of Gases 13.2 The Nature of Liquids 13.3 The Nature of Solids 13.4 Changes of State

13.1 The Nature of Gases > 2 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Kinetic Theory and a Model for Gases Do Now: 1.Draw a picture of a solid, a liquid, and a gas. 2.Describe the differences between a solid, a liquid, and a gas.

13.1 The Nature of Gases > 3 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Kinetic Theory and a Model for Gases kinetic energy: the energy an object has because of its motion Kinetic Theory: all matter consists of tiny particles that are in constant motion.

13.1 The Nature of Gases > 4 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Kinetic Energy and Temperature Average Kinetic Energy The average kinetic energy of the particles in a substance is directly related to the substance’s temperature. Absolute zero (0 K, or – o C) is the temperature at which the motion of particles theoretically ceases.

13.1 The Nature of Gases > 5 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Kinetic Theory and a Model for Gases Kinetic Theory of Gases 1.Gas particles are small, hard spheres with an insignificant volume. 2.The motion of particles is rapid, constant, and random 3.All collisions are elastic

13.1 The Nature of Gases > 6 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Gas Pressure Gas pressure: force exerted by a gas per unit surface area of an object. Units: 1 atm = 760 mm Hg = kPa

13.1 The Nature of Gases > 7 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Gas Pressure atmospheric pressure is the result of collisions of atoms and molecules in air with objects. barometer: device used to measure atmospheric pressure.

13.1 The Nature of Gases > 8 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. A pressure gauge records a pressure of 600 kPa. Convert this measurement to a.atmospheres b.millimeters of mercury 1 atm = 760 mm Hg = kPa Converting Between Units of Pressure Sample Problem 13.1

13.1 The Nature of Gases > 9 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Multiply the given pressure by the conversion factor. Calculate Solve for the unknowns. 2 b. 600 kPa × = 4501 mm Hg kPa 760 mm Hg 1 atm kPa a. 600 kPa × = 5.9 atm Sample Problem 13.1

13.1 The Nature of Gases > 10 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. END OF 13.1