Gas in gas
it is not gas it is just air
the gas powered air soft guns use CO2 or green gas
hydrogen, helium, hot air
nitrogen
freon
just about every kind of gas but the main is nitrogen then oxygen if you look on the peroidic table of elements there will be a group called the noble gases those are the gases in the air
Just plain old ordinary air, but heated by the flame of the burner (which I believe burns propane gas).
Gas is heavier than oxygen. Cold air is heavir than hot air
At reasonable temperature nitrogen is a gas. Most of the air is nitrogen.
air resistance
No Gas Just hot air which is why it is called a hot air balloon. If you were wondering hot air is lighter than cold air which makes it rise so when it is trapped inside the balloon the whole thing will rise.