Question

[Guest minyng]

If 50.75g of a gas occupies 10.0L at STP, what will be the volume in L occupied by 129.3 of the gas at STP?

[YT2095]

you`ll need to establish your factor 1`st by dividing the 10l by the 50.75

and then multiply by the 129.3

 

I hate maths but off the top of my head, I think the answer will be around the 25L mark (I Could be wrong tho!)

[mezarashi]

Sounds like a thermodynamics question. Assume that it is an ideal gas (if it isn't you have no equations, you need to look up tables like with water). Apply the ideal gas equation:

 

P1V1 = n1RT1

 

Work from there. You know P1 = P2, R = R, etc.

[gnpatterson]

No I think, there is no need to assume ideal gas as both samples are at STP

 

yt2095 is correct this is simple proportionality

 

The next logical step would be to calculate the average molar mass on the assumption that it is an ideal gas.

 

At 5.075 g/L it is about 4 times denser than air so it is something with an average molecular mass of 5.075 * 22.4 = 114

 

this is pretty heavy for a gas but not the heaviest (uranium hexafloride spings to mind)

 

a halo-carbon would be my bet

[DQW]

XeF6 is closer but still too heavy...

[gnpatterson]

I have often wondered if it is possible to have a liguid that so light and a gas so dense that the liquid is bouyant in the gas and if so what phenomena (micro-gravity style) you might observe. Or would it be just a exotic lava lamp?

[DQW]

I have often wondered if it is possible to have a liguid that so light and a gas so dense that the liquid is bouyant in the gas and if so what phenomena (micro-gravity style) you might observe. Or would it be just a exotic lava lamp?

Just looking into phase diagrams I find that the density of helium gas at 10 atm, 80 K is much bigger than that of liquid nitrogen (at same conditions, of course).

 

What phenomenon will you observe ? Buoyancy, I guess. The liquid will stay at the top of the container.

[gnpatterson]

There are two questions that need to be answered

 

1) in the condition that the liquid is significantly less dense than the gas--

 

Is there any difference in the physics of the "upside down liquid" for example if you bubble heavy gas through the light liquid and the bubbles fall to the bottom surface and they burst out of it, as they burst out does the spatter and pop of the bubble look the same a when we do it the normal way round.

 

2) in the condition that the liquid and gases have the same density

 

Does the physics vary from that seen in microgravity. We have all see astonauts squirting water into "zero gravity". When viscousity and surface tension are matched however it should be possible to see if a shaken container of droplets even looks the same and to probe it precisely by looking at how it scatters light.

 

The point is that while we can easily answer what should happen it would a circumstance in which our assumptions could be tested in extreme and the possiblity of new phenomena might arise.

 

as a micro-gravity experiment it would be interesting.

[YT2095]

we could get Really freaky and see if it would be possible for a Solid to float in a gas!

 

Lithium perhaps?

[DQW]

we could get Really freaky and see if it would be possible for a Solid to float in a gas!

With aerogel, that shouldn't be hard.

[YT2095]

yeah, that stuff is neat!

 

it`s like it`s there but it isn`t (if that makes sense), there`s some carbon based mesh that`s almost as light as air too, sometimes used in Laser testing for Photon "Kick" in solar sail design ideas (I love the Discovery channel) )

[gnpatterson]

I had never heard of aerogel before but it looks incredible.

 

However it would be no good for this purpose as it is an OPEN structure. If you took a lump of it that had been in air and put it in uranium hexafloride it would flost for a while as the air percolated out but it would sink slowly to the ground as the UF6 diffused in.

 

In fact bog standard polystyrene foam will just-about do the job.

 

The first demonstration of the principal of the heavier than air solid was of course by the Montgolfier brothers in 1783.