(B) All of the Molecules Have the Same Speed

AP Physics HW Name:

Kinetic Theory of Gases

1) An ideal gas is made up of N diatomic molecules, each of mass m. All of the following statements about this gas are true except:

(A) The temperature of the gas is proportional to the average translational kinetic energy of the molecules.

(B) All of the molecules have the same speed.

(D) The molecules make elastic collisions with each other.

(E) The average number of collisions per unit time that the molecules make with the walls of the container depends on the temperature of the gas.

2) If the temperature of an ideal gas is doubled, what happens to the root mean square speed of the molecules?

(A) It does not change

(B) It is multiplied by Ö2

(D) It is multiplied by 4

(E) Not enough information

3) If the temperature of an ideal gas increases, which of the following is true?

I. The gas molecules collide with the walls of the container more frequently.

II. The gas molecules exert more force on the walls of the container per collision.

III. The gas molecules lose more energy during each collision that they make with one another.

(A) I only (B) II only (C) III only (D) I and II (E) I, II and III

4) The average speed of the molecules of air in a room is on the order of the speed of sound. What is their average velocity?

Explain your answer.

5) The air in your room is composed mostly of oxygen (O2) and nitrogen (N2) molecules. The oxygen molecules are more massive than the nitrogen molecules. How do their root mean square speeds compare?

6) a) If the temperature of a room goes from 100 K to 200 K, does the total thermal energy of the room increase by a factor that is greater than, less than, or equal to 2? Explain.

b) If the temperature of a room goes from 100 °C to 200 °C, does the total thermal energy of the room increase by a factor that is greater than, less than, or equal to 2? Explain.