Is there a type of liquid that is less dense than a type of gas?

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Discussion Overview

The discussion revolves around the question of whether there exists a type of liquid that is less dense than a type of gas. Participants explore various examples of gases and liquids, focusing on their densities under standard temperature and pressure (STP) conditions.

Discussion Character

  • Debate/contested, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant questions if the gas form of uranium or other heavy atoms could be denser than liquid hydrogen.
  • Another participant states that tungsten hexafluoride is the densest known gas at 1.3 g/l, while the least dense liquid is likely some form of alcohol at approximately 0.78 g/cc, suggesting that no liquid is less dense than a gas under these conditions.
  • A different participant provides density values for liquid hydrogen (71 g/l) and gases like xenon (5.894 g/l) and radon (9.73 g/l), implying that liquid hydrogen is denser than these gases.
  • One participant expresses confusion regarding gas density, noting that gas is compressible and its density can increase under pressure, and mentions the lack of a clear boundary between liquid and gas at high temperatures.
  • Another participant emphasizes the importance of comparing densities at the same temperature, arguing that liquid hydrogen should not be compared to gases unless they are at the same conditions.
  • A later reply humorously suggests that if such a liquid existed, it would likely be widely known or featured in popular media.

Areas of Agreement / Disagreement

Participants do not reach a consensus; there are multiple competing views regarding the densities of gases and liquids, and the discussion remains unresolved.

Contextual Notes

Some limitations include the dependence on temperature and pressure conditions for density comparisons, as well as the potential for varying definitions of "liquid" and "gas" under different states.

Mattius_
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Would the gas form Uranium or any other heavy atom be more dense than the liquid form of hydrogen?
 
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The densest known gas is tungsten hexafluoride, at 1.3 g/l. The least dense liquid is probably some form of alcohol which comes in at ~.78 g/cc (780 g/l), so I'm going to have to say no. These figures are for STP; other temperature and pressure ranges may differ.
 
Liquid hydrogen is about 71 grams per liter. Xenon gas is 5.894 grams per liter at STP (I think). Radon is about 9.73 grams per liter.
 
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I am a little puzzled by the numbers for gas density. Gas is compressible, so the density would increase under pressure. Also I have a recollection (I was exposed to this a long time ago so my memory may be faulty) that at high temperture there is no sharp divide between liquid and gas, so that gas could be compressed to a much higher density.
 
That's why I specified that the values were given for STP (standard temperature and pressure). Liquid hydrogen doesn't count unless what you're comparing it to is at the same temperature. Otherwise, you're comparing apples to earthworms.
 
I feel like if there were we would have all seen the youtube video.
 

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