Chapter 8.3

Question 1

What are the assumptions made for the kinetic molecular theory of gases

Answer 1

1) Gases are made up of particles with volumes that are negligible compared to the container volume
2) Gas atoms or molecules exhibit no intermolecular attractions or repulsions
3) Gas particles are in continuous, random motion, undergoing collisions with other particles and container walls

4) Collisions between any two gas particles are elastic
- >there is conservation of momentum and kinetic energy

5) The average kinetic energy of a gas particle is proportional to the absolute temperature of the gas(in kelvins)
- >it is the same for all gases at a given temperature

Question 2

Why use root-mean-square speed instead of individual speeds of gases

Answer 2

• because there are a large number of rapidly and randomly moving gas particles
• > so it is hard to measure the speed of an individual gas molecule
• > therefore, we must combine the individual speeds together to get root-mean-square speed

Question 3

What does the kinetic molecular theory of gases predict about the mass of gases and their diffusion rates

Answer 3

• heavier gases diffuse more slowly than lighter ones

- >because of their differing average speeds

Question 4

What is defined as effusion

Answer 4

• flow of gas particles under pressure from one compartment to another through a small opening
• for two gases at the same temperature, the rates of effusion are proportional to the average speeds
• > therefore, larger molecules effuse more slowly