Why wouldn't we expect all the molecules in a gas to have the same speed?

Question

Does it have to deal with kinetic energy?

Answer 1

The temperature of a substance is the measure of the AVERAGE kinetic energies of the particles making up the substance.
The temperature of a gas is the measure of the average kinetic energy of the gas particles.

A gas at a uniform temperature should have some average kinetic energy. The key word being 'average'. Just because the average KE is ___ does not mean that there are not some particles which have higher KE and some which have lower KE.

Kinetic energy relates the energy posses by a moving particle to its mass and velocity.
KE = 1/2 mv^2
where m is the particles mass and v is the particles speed.
For a given gas, the particle mass should be constant, so the only thing which would effect the KE would be the particles speed.
So if we assume that there are x number of particles with KE > than the average, they must have a KE (and thus a speed) which is greater than that associated with the gasses temperature. And since if there are particles with KE > the average, then there must be particles with KE < the average, which must in turn have a lower speed.

Answer 2

I would go more on the temperature side. The hotter the faster, the colder ther slower. Or perhaps pressure. Gas in a large chamber would be faster than compressed gas. Kinetic energy is energy stored in motion. If the smaller chamber were to be under the same pressure and temperature, it could still be faster if it were in motion, hence kinetic energy. Otherwise, no.

Answer 3

Well, it depends on what fueled that gas. For example: a bean burrito? Too many prunes? You see, kinetic energy only comes into place when it is released into the atmosphere. Otherwise, it's still merely potential energy.

And engery is expensive. But bean burritos are not. Thusly and therefore, you can save money by first eating the bean burrito, then expelling the gas in a kinetic fashion. Which is, fashionable.

Answer 4

Because, like ping pong balls in a tornado, they bump into each other and everything else around. The motion of a particle in a gas is approximately random, and is called Brownian motion. Furthermore, a heavy molecule will move slower than a lighter one with the same energy.

It was Einstein's paper on Brownian motion that really got his physics career started.

Answer 5

till there have been a temperature or tension gradient, or another exterior tension performing on the gas molecules, you will anticipate all of them to have the same familiar velocity. i.e. if there have been a area of gas at bigger temperature than the rest, the molecules in that area would be moving swifter. in case you ought to map the speeds of all the molecules, you incredibly would not anticipate all of them to have the same prompt velocity, yet you will anticipate them to have the same familiar velocity, interior the absence of a few nonuniformity interior the ambience.

Answer 6

They do - well, on average, and speeds of individual particles follow a distribution around that average.

It's a bit logical it you think about it. Some particles will be moving freely, others will be colliding, others will be bumping against the walls of the enclosure (if), etc.