How Do You Measure the weight of a Helium or Hydrogen balloon?

Question

if u put it upside down on a measuring scale it would be measuring upthrust not weight or mass and if it were in a vacuum it would explode so how would you do it??

Answer 1

Use the molar-gas-volume. Measure the volume of the balloon, the air temperature, and the air pressure. Then use the ideal gas law to determine the number of moles of gas you have. Use the molar-gas-volume to calculate the number of grams through stoichiometry.

Or, use water displacement. Fill the balloon with the gas while the balloon is trapped under water. The change in volume of the water is due to the change in volume of the gas in the balloon. Then use the molar-gas-volume to calculate mass.