Week 10

Question 1

What is the kinetic theory of gases?

Answer 1

The kinetic theory of gases relates the observable or bulk
properties of gases - their pressure, temperature and volume – to
the motion of the molecules of the gas

Question 2

What is the pressure of a gas cause?

Answer 2

It is caused by molecules of the gas bouncing of the walls of their container, which leads to a force being exerted.

Question 3

What happens when a molecule bounces off a wall and what happens to its momentum at right angles?

Answer 3

Exerts a force on the wall and its momentum at right angles would be equal to the rate of change of momentum

Question 4

What is the formula for the rate of change of momentum?

Answer 4

F = d(mu)/dt

When mass is constant:
F=ma

When velocity is constant:
F = V x dm/dt

dm/dt: Change of mass over time

Question 5

What is pressure in relation to molecules?

Answer 5

Pressure is the average force exerted by molecules on the walls / area of the wall

Question 6

What is the formula for change in momentum and derive it?

Answer 6

Change in p = m0 x v
m0 = Initial mass
v = velocity

Formula for p before collision:
p = m x v
Fomula for p after collision:
p = - x m0 x v

Question 7

What are the assumptions we make?

Answer 7

-The volume of the molecule is negligible since its very small
-Molecules behave like perfectly elastic spheres
-Molecules do not interact with eachother
-Duration of a collision

Question 8

Derive slide 10