The Gas State and Kinetic Molecular Theory (KMT)

1. The Gas State and Kinetic Molecular Theory (KMT) Lesson 1 Unit 5 Gases and Atmospheric Chemistry

2. The States of Matter Ionic Compounds: contain strong electrostatic attractions and are therefore found in the solid state at room temperature. They have high boiling points (e.g. NaCl(s)) Polar Molecules: These compounds contain permanent dipoles and form strong dipole-dipole intermolecular bonds. They are found in the liquid or solid state but have a lower boiling point. (e.g. H2O (l)) Non-polar Molecules: These have no dipoles and contain very weak intermolecular bonds. They are usually gases. (e.g. H2(g), Cl2(g) , CO2 (g)). Most substances can exist in the solid, liquid or gas states. Recall that the attractions between particles influence the state each substance is in at room temperature:

3. The States of Matter • Gas, Liquid, and Solid- there is also a fourth; it is called a plasma which has charged particles that can conduct electricity and are influenced by magnetic fields. It is similar to a gas in its properties

5. The Motion of Particles: Rotational Motion: • spinning motion of particles. Translational Motion: • straight-line motion from place to place. Vibrational Motion: • back-and-forth motion of particles.

9. Kinetic Molecular Theory of Gases • 1. A gas consists of particles in constant, random, straight-line motion; they collide with each other and with the walls of the container

10. 2. Gas particles influence each other only by collision; they exert no other forces on each other.

11. 3. All collisions between gas particles are perfectly elastic; all kinetic energy (energy of motion) is conserved.

12. 4. The volume actually occupied by the particles of a gas is negligible; the vast majority of the volume of the gas is empty space through which the gas particles are moving.

13. 5. Particles of different gases have equal kinetic energies at the same temperature.

14. Therefore, according to this theory, an ideal gas behaves much like billiard balls on a pool table.

15. Gas Pressures • In the KMT, pressure is the force exerted against the wall of a container by the continual collision of molecules against it.  • THE COLLAPSING CAN DEMO

16. Homework • Read 416 – 422 • # 1, 2, 3 (a,b), 4, 5 on pg. 422.