KMT Module Objectives

Kinetic Molecular Theory explains the macroscopic properties of gases and can be used to understand and explain the gas laws.

LEARNING OBJECTIVES

Express the five basic assumptions of the Kinetic Molecular Theory of Gases.

 

KEY TAKEAWAYS

Key Points

  • Kinetic Molecular Theory states that gas particles are in constant motion and exhibit perfectly elastic collisions.
  • Kinetic Molecular Theory can be used to explain the different states of matter - Solid, Liquid, Gas.
  • The average kinetic energy of a collection of gas particles is directly proportional to absolute temperature only.

Key Terms

  • ideal gas: a hypothetical gas whose molecules exhibit no interaction and undergo elastic collision with each other and the walls of the container
  • macroscopic properties: properties that can be visualized or measured by the naked eye; examples include pressure, temperature, and volume

Previously, we focused on the microscopic properties of matter—the properties of individual atoms, ions, and molecules. We will now focus on macroscopic properties—the behavior of mixtures with large numbers of atoms, ions, or molecules. An understanding of macroscopic properties is central to an understanding of chemistry. Why, for example, are many substances gases at room temperature whereas others are liquids or solids? (Imagine our classroom - all at the same temperature, but filled with solid desks and chairs, liquid water in beakers, and gases filling the atmosphere.)

We will examine each form of matter—gases, liquids, and solids—as well as the nature of the forces, such as hydrogen bonding and electrostatic interactions, that hold molecular and ionic compounds together in these three states.