CHM 2045C Module Six: The Gaseous State (Chapter 12) Sample Answers
Module Six: The Gaseous State (Chapter 12)
______(60) Total = ______%
Module Six- Part A: Kinetic Molecular Theory 5 points
State three assumptions of the Kinetic Molecular theory as stated in the book in Section 6.1 Page 567or as written on the board (5) or the answer sheet from CHM 1025C. The 2045C text combines the 5/6 statements in the 1025C text. You may write either set:
From CHM 1025C:
1. Gases are composed of molecules*. The distance between the molecules is very-very great compared to the size of the molecules themselves, and the total volume of the molecules is only a very-very small fraction of the entire space occupied by the gas. Therefore, considering volume, we are primary considering empty space. (This assumption explains why gases are highly compressed and have very low densities.)
2. No attractive forces exist between molecules in a gas. (This is what keeps a gas from spontaneously becoming a liquid.)
3. The molecules of a gas are in a state of constant, rapid motion, colliding with each other and with the walls of the container in a perfectly random manner. (This assumption explains why different gases normally mix completely. The collisions between molecules and the walls of the container account for the pressure exerted by the gas.)
4. All of these molecular collisions are perfectly elastic. As a result, the system as a whole experiences no loss of kinetic energy, the energy derived from the motion of a particle.
5. The average kinetic energy per molecule of a gas is proportional to the absolute temperature, and the average kinetic energy per molecule is the same at a given temperature and pressure for all gases.
From 2045C text Page 567
a) Gases consist of particles (molecules or atoms), whose separation is much greater than the size of the particles themselves.
(b) The particles of a gas are in continual, random, and rapid motion. As they move, they collide with one another and with the walls of their container, but they do so without energy loss.
(c) The average kinetic energy of gas particles is proportional to the gas temperature. All gases, regardless of molar mass, have the same average kinetic energy at the same temperature.
When we think of molecules of elemental gases, we usually think of the diatomic gases such as nitrogen, oxygen, hydrogen, etc. The Nobel gases exist as monoatomic gases such as Helium, Neon, etc.