Section 13.3 Using a Model to Describe Gases 1.List the physical properties of gases 2.Use the KMT to explain the physical properties of gases. Objectives

Section 13.3 Using a Model to Describe Gases Kinetic Molecular Theory Kinetic Molecular Theory – matter is made up of particles and those particles are in constant motion. The KMT is used to describe the properties of gases based upon the behavior of individual gas particles.

Section 13.3 Using a Model to Describe Gases Kinetic Molecular Theory 1.Gases are made up of tiny particles. - Usually atoms or molecules

Section 13.3 Using a Model to Describe Gases Kinetic Molecular Theory 2.The particles of a gas are far apart from each other. The volume of gas particles is insignificant relative to the space between the particles

Section 13.3 Using a Model to Describe Gases Kinetic Molecular Theory 3.The particles of a gas are in constant motion and collide with each other and the walls of their container. The collisions are elastic; no K.E. is lost. Collisions exert a force - pressure Specian's Phun machines: Ideal gas - YouTube

Section 13.3 Using a Model to Describe Gases Kinetic Molecular Theory 4.The particles of a gas do not exert any force on each other except when they collide.

Section 13.3 Using a Model to Describe Gases Kinetic Molecular Theory 5.Temperature is a measure of the average kinetic energy of the particles of a gas. Kinetic Energy in a Gas - YouTube

Section 13.3 Using a Model to Describe Gases B. The Kinetic Molecular Theory of Gases

Section 13.3 Using a Model to Describe Gases C. The Implications of the Kinetic Molecular Theory Meaning of temperature – Kelvin temperature is directly proportional to the average kinetic energy of the gas particles Relationship between Pressure and Temperature – gas pressure increases as the temperature increases because the particles speed up Relationship between Volume and Temperature – volume of a gas increases with temperature because the particles speed up

Section 13.3 Using a Model to Describe Gases Gases do not behave ideally under conditions of high pressure and low temperature. Why? D. Real Gases

Section 13.3 Using a Model to Describe Gases At high pressure the volume is decreased –Molecule volumes become important –Attractions become important D. Real Gases