Thank you very much for your reply.

Size and shape. rectangular is good. would want to see the difference between a square container verses a tall thin rectangular one..

The number of particles would depend on the size and pressure. Could you maybe set Gas A as the basis that fills the remaining volume, and then allow for Gas B and C to be filled up to the whole volume as well. i.e. if the volume can hold 1000 molecules and you specify that Gas B has 100 molecules and Gas C has 200 then Gas A would be set to 700. ranges would then be 0-1000 for each B and C with A set automatically. Would be good to have as big a volume as is possible though I understand that the bigger the more complex the calculations. What sort of size would be reasonable? is 10 litres of space too much? 20L?

Temperature is the average temperature / energy of the molecules.

Would be good to be able to speed up the simulation of the time so a time factor could be written in to i.e. 1s = 1h in simulation time etc.

Physical properties:

Gasses will be molecular mass 2-50.

temp 200 K to 400K

simulation time 0 s to few days.

Three different colours for the different gasses, say Red, Blue, Yellow

Size would be rectangular from tall thin to wide flat as big as is reasonable, set by the volume. I'll run it direct off a PC so much more RAM for the calculations than off a website

Hope this helps.

Charlie.