A-level Physics (Advancing Physics)/Kinetic Theory/Worked Solutions

1. Five molecules are moving at speeds of 1,5,6,8, and 36ms−1. What is their mean square speed?

2. What is the mass of one molecule of N2 (atomic mass 14, 1u = 1.66 x 10−27kg)?

3. Atmospheric pressure is 101,325 Pa. If one mole of Nitrogen takes up 2.3 m3 at about 10 °C, what is the mean square speed of the molecules in the air outside, assuming that the atmosphere is 100% nitrogen (in reality, it is only 78%)?

4. What is the average speed of a nitrogen molecule under the above conditions?

5. The particles in question 1 are duplicated 3000 times. If they have a completely unrealistic mass of 1g, what is their pressure when they are crammed into a cube with side length 0.5m?