I need to lift a 1 kg item into the air using a hydrogen filled balloon. what is the lifting capacity of hydrogen? haw many 20" diameter-10gm-balloons do i need?
2006-08-21 19:31:44 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Physics
Hydrogen gas (H2) has a molar mass of 2.02 grams per mol.
Air is a mixture of ~20% Oxygen gas (O2) and ~80% Nitrogen gas (N2) and ha an average molar mass of about 28.82 grams per mol.
The difference in the two gasses molar masses will give you the lifting power of 1 mole of Hydrogen gas in an air atmosphere when both gasses are under the same temperature and pressure.
1 mole of Hydrogen gas has a "lifting power" of about 26.80 grams per mole.
At STP (standard temperature of pressure), 1 mole of an ideal gas has a volume of 22.4 Liters which would mean that Hydrogen gas would have a lifting power of about 1.20 grams per Liter (@ STP).
1 kg = 1000 grams.
It would take about 833.3 Liters of Hydrogen to lift 1 kg at STP, this does not take into account the weight of the balloon holding the Hydrogen gas nor does it take into account any extra mass which might be attached (string, ....).
A 20" diameter sphere has a volume of,
4/3 * pi * r^3, with r being the radius,
volume = 4/3 * pi (10")^3
volume = 4189 cubic inches.
1 in^3 = 0.016387 Liters,
4189 in^3 = about 68.65 Liters
meaning that you would need about 14 balloons in total.
14 Balloons will hold 961.1 Liters of H2 with a lifting power of about 1153.3 grams. The balloons themselves will have a mass of 140 grams, plus the 1 kg mass being lifted, making the total 1140 grams.
2006-08-22 03:24:51 · answer #1 · answered by mrjeffy321 7 · 0⤊ 0⤋
It's like any other flotation problem. Calculate the mass of the balloon and the hydrogen in it (use PV = nrt to get the number of moles of hydrogen and figure 1 g/mole. You'll probably have to measure the P for a full balloon), and subtract that from the mass of air that the volume of the balloon displaces.
The difference is it's lifting capacity.
Doug
2006-08-21 20:16:00 · answer #2 · answered by doug_donaghue 7 · 0⤊ 0⤋
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Yes, Hydrogen is lighter than helium. Therfore the upthrust caused by the difference in mass or better density is greater than that of helium. Hydrogen is lightest thing known to man because it consists of 1 proton and one electron, unless some scholar of relativity corrects me it is the lightest possible element. After the Hindenburg (I think) disaster helium is used because it is not as flammable as Hydrogen
2016-04-03 09:23:50 · answer #3 · answered by ? 4 · 0⤊ 0⤋