1. The Kinetic-Molecular Theory of Matter (KMT)

2. What is the kinetic molecular theory? Theory developed by scientists to explain the behavior of atoms that make up matter gases KMT is used to describe interactions between molecules in solids, liquids, and gases

3. 5 Assumptions of KMT for Gases ideal gases NOTE: KMT only applies to ideal gases. tiny far apart no volume 1)Gases are made of tiny particles that are far apart from each other (almost like the particles have no volume). elastic collisions (no loss of kinetic energy). 2)Collisions between gas particles or between gas particles and the walls of their container are elastic collisions (no loss of kinetic energy). kinetic(motion) 3) Gas particles are in constant, rapid, and random motion because they have kinetic (motion) energy.

4. 5 Assumptions Cont’d no intermolecular forces 4) There are no intermolecular forces (IMFs) between gas particles. Temperature 5) Temperature affects the amount of motion the gas particles have (which makes perfect sense since temperature is a measure of the amount of kinetic energy in a sample). POP QUIZ: POP QUIZ: What are the four types of intermolecular forces?

5. Properties of Gases & KMT Expansion Expansion: Gases do not have a definite shape or a definite volume and they will completely fill any container. Fluidity Fluidity: Gas particles glide easily past one another, like liquids. Low Density Low Density: The density of gases is about 1/1000 the density of solids and liquids. POP QUIZ: POP QUIZ: Which assumptions of KMT explain these?

6. More Properties Compressibility: Compressibility: The volume of gases can be greatly decreased without liquefying. Diffusion and Effusion: Diffusion and Effusion: Gases spread out and mix with each other, even without being stirred. POP QUIZ 1: POP QUIZ 1: What is the difference between diffusion and effusion? POP QUIZ 2: POP QUIZ 2: Which assumptions of KMT explain these properties?

7. Real Gases real gas A real gas is a gas that does not completely follow the five assumptions of KMT. volumeIMFs Real gases have volume and have IMFs. – Low pressure high temperatures – Low pressure and high temperatures make real gases almost like ideal gases less polar – The less polar a gas molecule is, the more like an ideal gas it is (EX – noble gases and diatomic elements) POP QUIZ 1 POP QUIZ 1: Explain why low pressures and high temperatures would be good. POP QUIZ 2 POP QUIZ 2: Explain why less polarity would be good. POP QUIZ 3 POP QUIZ 3: How do you tell if a gas is polar or nonpolar