General, Organic, and Biological Chemistry Fourth Edition Karen Timberlake Chapter 7 Gases 7.1 Properties of Gases Lectures © 2013 Pearson Education, Inc.

Common Gases Of the elements on the periodic table, some exist as a gas at room temperature, these include the Noble Gases, Group 8A (18), H2, N2, O2, F2, Cl2, and many oxides of nonmetals such as CO, CO2, NO, NO2, SO2, and SO3. 2

Gases and Environmental Concerns Some gases are responsible for environmental and health concerns including methane, CH4, chlorofluorocarbons (CFCs), nitrogen oxides found in smog, and volatile organic compounds (VOCs), such as compounds found in paint thinners. 3

Kinetic Theory of Gases A gas consists of small particles that move randomly with high velocities. have essentially no attractive (or repulsive) forces toward each other. have a very small volume compared to the volume of the containers they occupy. are in constant motion. have kinetic energies that increase with an increase in temperature. 4

Properties of Gases Gases are described in terms of four properties: 1. pressure (P), 2. volume (V), 3. temperature (T), and 4. amount (n). 5

Learning Check Identify the property of a gas (temperature, volume, or pressure) that is described by each of the following: A. increases the kinetic energy of gas particles B. the force of the gas particles hitting the walls of the container C. the space that is occupied by a gas 6

Solution Identify the property of a gas that is described by each of the following: A. increases the kinetic energy of gas particles temperature B. the force of the gas particles hitting the walls of the container pressure C. the space that is occupied by a gas volume 7