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Topic: about hydrogen gas  (Read 16977 times)

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Offline bg105ee056

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about hydrogen gas
« on: December 07, 2006, 07:28:24 AM »
how much hydrogen gas (volume) would be required to lift a mass of 1 K.g. Like in the case of an hydrogen balloon.

Offline Borek

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Re: about hydrogen gas
« Reply #1 on: December 07, 2006, 09:10:27 AM »
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Offline billnotgatez

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Re: about hydrogen gas
« Reply #2 on: December 08, 2006, 08:00:55 AM »

Offline Donaldson Tan

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Re: about hydrogen gas
« Reply #3 on: December 08, 2006, 02:09:53 PM »
The Ideal Gas Equation will give you a good estimate of the volume.
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Offline kommyching

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Re: about hydrogen gas
« Reply #4 on: July 01, 2008, 10:10:09 AM »
As the molar mass of hydrogen gas is 2 grams/mole.
1000 kg of hydrogen gas contains 500 moles of hydrogen molecule.
Under room condition(25 Degree Celsius and 1 atmospheric pressure), 1 mole of gas molecule occupy 24.0 cubic decimeter.
Therefore 500 moles= 500*24 cubic decimeter=1200 cubic decimeter.

Offline Borek

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Re: about hydrogen gas
« Reply #5 on: July 01, 2008, 01:38:18 PM »
As the molar mass of hydrogen gas is 2 grams/mole.
1000 kg of hydrogen gas contains 500 moles of hydrogen molecule.

No. What is difference between g and kg?

Not that it is in any way related to the original question.
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Offline Mitch

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Re: about hydrogen gas
« Reply #6 on: July 07, 2008, 02:52:55 AM »
Umm... I actually wouldn't know how to approach this one, any suggestions? And if anyone says look at #1 in my sig....
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Offline sjb

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Re: about hydrogen gas
« Reply #7 on: July 07, 2008, 03:35:12 AM »
Umm... I actually wouldn't know how to approach this one, any suggestions? And if anyone says look at #1 in my sig....

Something along the lines of http://www.chem.hawaii.edu/uham/lift.html ? perhaps - but the figures seem a little low (not enough lift)

S

Offline Borek

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Re: about hydrogen gas
« Reply #8 on: July 07, 2008, 05:25:55 AM »
Lift is the difference between mass of the liquid (gas) displaced and mass of the object (or buoyancy minus mass of the object itself). So, volume V of hydrogen displaces V air and lift is V(dair-dhydrogen). Density of air at STP is around 1.29 g/L, density of hydrogen at STP - around 0.089 g/L. That gives lift of 1.2 g/L, you need 1kg, so 830 L will do. That's neglecting mass of the baloon.

Densities can be easily calculated from pV=nRT and n=mass/molar mass, or even simpler from d = molar mass/22.4.
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