Kinetic Molecular Theory Phase diagrams

Engage 1. What inflates the balloon? 2. Where is the gas coming from? 3. Which gas production is a physical change? Why? 4. Which gas production is a chemical change? Why? 5. If you could zoom in really far inside a balloon, what do you think the air inside would look like? 6. How will you describe the gas inside the balloon? Describe at least 3 behavior of gas molecules.

Explore Draw the phase diagram in notebooks and label the parts.

Explain: Kinetic Molecular Theory of Matter Kinetic energy: the energy an object has because of its motion Kinetic molecular theory: states that all matter consists of tiny particles that are in constant motion Kinetic molecular theory as it applies to gases includes five postulates. ◦ 1. The particles in a gas are considered to be small, hard spheres with an insignificant volume.  The distance between particles in a gas is larger than the distance between particles in a solid or liquid.  There is only empty space between the particles. ◦ 2. No attractive or repulsive forces exist between the particles of a gas. ◦ 3. The motion of the particles in a gas is rapid, constant, and random.  Gases fill their containers regardless of shape and volume.  The particles travel in straight-line paths until they collide with another particle or another object, such as the wall of their container.  Their path of uninterrupted travel in a straight line is very short ◦ 4. All collisions between particles in a gas are perfectly elastic.  During an elastic collision, kinetic energy is transferred without loss from one particle to another, and the total kinetic energy remains constant. ◦ 5. The Kelvin temperature of a substance is directly proportional to the average kinetic energy of the particles of the substance.  The particles in helium gas at 200 K have twice the average kinetic energy as the particles in helium gas at 100 K.

Elaborate Draw a chart and in your own words, summarize the 5 postulates of the Kinetic molecular theory (5 minutes only) Answer the following questions: ◦ What is the kinetic theory of matter? ◦ How is the motion of the particle affected by temperature? ◦ Does the 5 postulates apply to all phases of matter? ◦ What is meant by the term “elastic”?