- #1
men5j2s
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- TL;DR Summary
- 1atm of air + 1atm of HE in a 17.5ml vessel = a mass gain of ~2.9mg
Hi All,
I'm trying to answer a question once and for all that has caused more debate than it ever should have (talking about an internal debate)...
If I fill a sealed vessel (say an aluminium vessel with appox. 17.5ml of internal volume) with varying amounts of helium ( 1bar, 2bar, 3bar ... 10bar), will I see a net mass gain or loss?
My current understanding is as follows:
I'm trying to answer a question once and for all that has caused more debate than it ever should have (talking about an internal debate)...
If I fill a sealed vessel (say an aluminium vessel with appox. 17.5ml of internal volume) with varying amounts of helium ( 1bar, 2bar, 3bar ... 10bar), will I see a net mass gain or loss?
My current understanding is as follows:
- The sealed vessel is displacing a volume of air (assuming a vacuum), and therefore will have some buoyancy! (approx -2.3mg)
- The weight of the vessel is larger, so it won't float, but the buoyancy effect can be measured!
- Adding air to 1atm (~1bar absolute) inside the vessel, means density equilibrium inside and outside the vessel, so no buoyancy effect!
- Adding helium to 2atm (on top of the 1atm of air) will simply add more moles to a closed system that is already overcoming any buoyancy effect, by virtue of the 1atm of air that was in there, therefore there will be a net mass gain.
- I should end up with a weight gain of ~2.9mg