The Kinetic-Molecular Theory of Matter By: Allyn, Maddi, Megan, Rebecca, Reesha

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Study the kinetic molecular theory as it applies to gas molecules Determine the difference between a real and ideal gas How the kinetic energies relate to temperatures and mass What You WILL Learn...

Kinetic Molecular Theory - is based on the idea that particles of matter are always in motion. Ideal Gas - hypothetical gas that perfectly fits all the assumptions of the kinetic-molecular theory Real Gas - a gas that does not behave completely according to the assumptions of the kinetic-molecular theory Definitions

The Kinetic- Molecular Theory of Gases is based on five assumptions. The Five Assumptions Gases consist of large numbers of tiny particles that are far apart relative to their size. Collisions between gas particles and between particles and container walls are elastic collisions. An elastic collision is one in which there is no net loss of total kinetic energy. Gas particles are in continuous, rapid, random motion. They therefore possess Kinetic energy, which is energy of motion. There are no forces of attraction between gas particles. The temperature of a gas depends on the average kinetic energy of the particles of gas. The Kinetic- Molecular Theory of Gases is based on five assumptions. Reesha - present

KE = 1/2mv2 m is the mass of the particle and v is the speed All particles of a specific gas have the same mass and their kinetic energies depend on their speeds Average energies and kinetic energies of gas particles increase with an increase in temperature and decrease with a decrease in temperature Gases at the same temp have the same average kinetic energy So, with the same temp, the lighter gas particles will have higher average speeds than do heavier gas particles Kinetic Energy

Physical Properties of Gases Expansion - Gases do not have a definite shape or volume and so they completely fill any container in which they are enclosed, and they take its shape. Fluidity - Gas particles glide easily past one another and this flow causes gases to behave as liquids do. Low Density - The particles are far apart in the gaseous state. The density of the substance is about 1/1000 the density of the same substance in the liquid or solid state. Compressibility - during compression, the gas particles, which are initially very far apart, are crowded closer together and the volume can be greatly decreased Physical Properties of Gases

Physical Properties con’t Diffusion - The mixing of particles of 2 substances caused by their random motion Ex. if the lid is removed from a bottle of ammonia, the ammonia gas will mix uniformly and spread throughout the room Effusion - the process by which gas particles pass through a tiny opening Ex. Particles in a helium balloon easily escape through the microscopic holes in the balloon because the helium atoms are so small and light Physical Properties con’t

Deviation of Real Gases from Ideal Behavior At high pressures and low temperatures the gas particles become closer together and deviate from the ideal gas behaviour The more polar the molecules of a gas are, the greater the attractive forces between them and the more the gas will deviate from ideal gas behavior Ex: Ammonia(NH3) and water vapor are highly polar gases and so deviate from ideal behavior Deviation of Real Gases from Ideal Behavior