# If Ununoctium could be perhaps denser than water

1. May 7, 2007

### Ununnonium

I was wondering, is it possible to have a gas denser than water? I once saw a video where they had 6 balloons. The first contained Helium and when released, it floated to the ceiling. The neon did the same. Argon slowly floated down. Krypton was interesting to see but not as much as the Xenon. The Xenon fell stait to the ground without a bounce as it is nicknamed, "The Lead Balloon". They had no Radon although. . I'm assuming if one were to follow the pattern, Radon would be rediculusly sink and that lead me to wonder if Ununoctium could be perhaps denser than water. Any thoughts?

2. May 8, 2007

### daveb

Well, under the right circumstances many gasses are denser than water, such as in a tank of compressed gas.

3. May 8, 2007

### Ununnonium

I meant in its natural state

4. May 8, 2007

### mrjeffy321

Why would you assume it to [possibly] be more dense than water?
Water, after all, is fairly dense (1 kg / Liter).

If we approximate the gas to be an ideal gas (and what better gas to approximate this on than a noble gas), then we can estimate its density at STP by assuming that 1 mole of the gas has a volume of 22.4 Liters.
1 mole of the element #118 (provisionally named, "Ununoctium") has a molar mass of 294 g/mol of its theoretical most stable isotope.

Density = mass / volume
For 1 mole at STP,
Density = (294 g) / (22.4 Liters)
Density = 13.13 g/Liter
Which is a pretty high density for a gas, but it is still well below the density of water.

5. May 8, 2007

### Ununnonium

So it is possible to have a bubble under water?

6. May 8, 2007

### Hootenanny

Staff Emeritus
Where else do you usually have bubbles....?

[sorry couldn't resist]

7. May 8, 2007

### Ununnonium

:) A sinking bubble?

8. May 24, 2011

### Mr. Forte

Re: Ununoctium

According to that trend, ununoctium could be denser than water but we would probably not know since the only ununoctium ever synthesized was only 3 (mabye 4) atoms of Ununoctium-294 with a half-life of 890 microseconds.
That is a very interesting idea though.

9. May 25, 2011

### aroc91

Re: Ununoctium

Way to revive a 4 year old thread. lol