21. Kinetic Theory of Ideal Gases

(II) At about what pressure would the mean free path of air molecules be

(b) equal to the diameter of air molecules, ≈ 3 x 10⁻¹⁰ m? Assume T = 20° C .

(I) What speed would a 1.5-g paper clip have if it had the same kinetic energy as a molecule at 22°C?

(II) (b) What is the total translational kinetic energy of 1.0 mol of N₂ molecules at 25°C?

(II) A 1.0-mol sample of helium gas has a temperature of 18°C.

(a) What is the total kinetic energy of all the gas atoms in the sample?

(I) Approximately how long would it take for the ammonia of Example 18–9 to be detected 1.0 m from the bottle after it is opened? What does this suggest about the relative importance of diffusion and convection for carrying odors?

(II) A 1.0-mol sample of helium gas has a temperature of 18°C.

(b) How fast would a 65-kg person have to run to have the same kinetic energy?

A 0.40-kg trash-can lid is suspended against gravity by tennis balls thrown vertically upward at it. How many tennis balls per second must rebound from the lid elastically, assuming they have a mass of 0.060 kg and are thrown at 15 m/s?