To an order of magnitude, how many helium-filled toy balloons would be required to lift you? Because helium is an irreplaceable resource, develop a theoretical answer rather than an experimental answer. Assume that you have a mass of approximately 70 kg, the radius of a balloon is 12.5 cm, the helium is at STP and it is immersed in air at 0°C and 1 atm.

Question

I used the equation for buoyant force to find the buoyant force of one balloon. The equation is Buoyant force= (density of air)*(acceleration due to gravity)*(Volume displaced)

The weight of the person is 686/buoyant force of one one balloon= # of balloons.

I got 6710 balloons, but this is incorrect.

Answer 1

But you left out the weight of the Helium

At stp a mole of Helium is 22.4 liters
and a mole of He is 4 grams / mol

Answer 2

I included the weight of helium, (which is minuscule) and it still did not work.

Answer 3

Just as an update, I did include the weight of the helium, but I did it incorrectly. Thanks for making me check it again. Really, I am truly grateful. THANKS DAMON.

Answer 4

You are welcome :)