posted by confused student .
How can you measure the amount of a gas?
Know the volume of the container, V. Measure the pressure, P, and the temperature, T. Then use the ideal gas law n = PV/RT
n is the number of moles of gas. That formula works no matter what the gas is.
If you need to know the particular amount one type of gas in a mixture, various analytical methods can be used, such as spectroscopy, cryotrapping or chemical means.