Question

average kinetic energy of diatonic molecule at high temperature​

Answer 1

Answer:

Explanation:

Consider a cube-shaped box, each side of length L, filled with molecules of an ideal gas. A molecule of ideal gas is like a bouncy rubber ball; whenever it's involved in a collision with a wall of the box, it rebounds with the same kinetic energy it had before hitting the wall. Similarly, if ideal gas molecules collide, the collisions are elastic, so no kinetic energy is lost.

Now consider one of these ideal gas molecules in this box, with a mass m and velocity v. If this molecule bounces off one of the walls perpendicular to the x-direction, the y and z components of the molecule's velocity are unaffected, and the x-component of velocity reverses. The molecule maintains the same speed, because the collsion is elastic. How much force, on average, does it exert on the wall?

To answer this we just have to think about momentum, and impulse. Momentum is a vector, so if the particle reverses its x-component of momentum there is a net change in momentum of 2 m vx. The magnitude of the average force exerted by the wall to produce this change in momentum can be found from the impulse equation: