Gas with greatest molecular weight

In summary, the room-temperature gas with the greatest molecular weight is likely one of the heavy-metal hexa halides, such as WF6 or PtF6, with molecular weights of 298 g/mol and 309 g/mol respectively. However, PtF6 is only a liquid within a small temperature range and UF6 and PuF6 have even higher molecular weights and are gases at slightly lower temperatures.
  • #1
Loren Booda
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What room-temperature gas has the greatest molecular weight?
 
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  • #2
Atomic weight of Rn is 222. That's right up there with the giants.

I think the record is held by one of the heavy-metal hexa halides. The halide ions provide a nice repulsive shield.
 
  • #3
Could be WF6 (tungsten hexafluoride) at 298 g/mol.
 
  • #4
Since we're talking metal fluorides, PtF6 = 309 g/mol
 
  • #5
shrumeo said:
Since we're talking metal fluorides, PtF6 = 309 g/mol

But it's a solid at room temp. In fact it is liquid only from 63C to 69C, a pretty small range, wot ?
 
  • #6
yeah, i guess 70C would be a pretty hot room
well, if we want to stretch it a little UF6 and PuF6 are dern heavy and gases right above room temp, if I'm not mistaken (again) their boiling points are in the 30s or 40s.
 

FAQ: Gas with greatest molecular weight

What is the gas with the greatest molecular weight?

The gas with the greatest molecular weight is uranium hexafluoride (UF6) with a molecular weight of 352 g/mol.

How does the molecular weight of a gas affect its behavior?

The molecular weight of a gas affects its behavior by influencing its density and how it interacts with other molecules. Heavier gases with higher molecular weights tend to be denser and move slower, while lighter gases with lower molecular weights move faster and spread out more easily.

What are some common gases with high molecular weights?

In addition to uranium hexafluoride, other common gases with high molecular weights include sulfur hexafluoride (SF6), xenon (Xe), and radon (Rn).

Can the molecular weight of a gas change?

Yes, the molecular weight of a gas can change if it undergoes a chemical reaction or if it is exposed to extreme temperatures or pressures. However, the molecular weight of a pure gas is constant.

How is the molecular weight of a gas calculated?

The molecular weight of a gas is calculated by adding the atomic weights of all the elements in its chemical formula. The atomic weights can be found on the periodic table of elements.

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