Question

Your lab has two pressurized gas cylinders, each containing a different gas. describe an experiment that could be used to determine whether each gas is less dense than air.

Answer 1

The easiest way is to fill two very light globes, each with a different gas.

Blow globe 1 with gas from the cylinder marked with label 1, and blow glove 2 with gas from the cylinder marked with label 2.

If a globe ascends in the air, it is because its gas is less dense than air.

Inflate the globes quite enough to be sure that the mass of the rubber of the globe is not important relative to the mass of  gas and so it does not change the results. If you obtain a result where the globe does not have a cliea ascending or descending motion, you can inflate more the globe and it shouuld start to rise if the gas really is less dense than air.