# Trying to simulate gas

1. Oct 27, 2011

### Tom83B

Hi, I'm trying to simulate different expansions and processes in gas and I have 3 questions:

If the average distance, that a molecule goes without hitting another one is $l$ (by the way, could you please tell me what this distance is called in english?) and $x$ is the distance it's already passed without hitting another molecule, is the probability, that it hits a molecule at the current distance $(\frac{1}{2})^{x/l}$? (taken from the assumtion, that it passes the distance $l$ with a 50% probability)

Is it useful (/common practice) to distribute the velocities of the molecules correspondently with the Maxwell-Boltzmann distribution or can I just give every molecule the same, average speed?

How do I proceed with the collision of two molecules? From what I've heard I want to calculate the probability that it hits another one, get a random number from 0 to 1 and find out if it hit something. But what next? How do I choose the molecule that it has hit?

2. Oct 27, 2011