Gas Laws Model Answers

Question 1

Define mean square speed

Answer 1

The sum of the squares of the molecular speeds divided by the number of molecules

Question 2

Why do the molecules of two different gases at the same temperature have different mean square speeds?

Answer 2

Since the temperatures are the same, the average kinetic energy of the molecules is the same in each gas
However, the mass of the molecules is different and so the mean square speeds must be different to give the same kinetic energy

Question 3

State and explain the effect that decreasing its temperature has on the pressure of a gas, using kinetic theory.

Answer 3

The pressure of the gas will decrease
Gas molecules will hit walls of container with lower speed and lower frequency
Thus the force experienced by the walls of the container will decrease, giving a lower pressure