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35 votes
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Which is the densest gas known?

Perfluorobutane is inert and has almost twice the density of sulfur hexafluoride. It is non-toxic enough that it is used in fire extinguishers and injected as a contrast agent for ultrasound. Boiling ...
Jonathan Ray's user avatar
31 votes

Why does a 57.15% ABV spirit (ethanol+water) have a density of 923 kg per cubic meter?

There is nothing wrong with your calculations: but some liquids don't play nice Your calculations are, likely, correct. But liquids, unlike ideal gases, don't necessarily obey simple rules when mixed. ...
matt_black's user avatar
20 votes
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What is the smallest molar volume?

Boron is a covalent solid with high melting point, like diamond (though not quite), and hence its crystals are hard to make. Unlike diamond crystals, they are not nice and probably wouldn't make a ...
Ivan Neretin's user avatar
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18 votes

What is the least dense liquid under normal conditions?

Isopentane $\ce{C5H12}$ has the density of $0.6201~\mathrm{g\,cm^{-3}}$ at $20~\mathrm{^\circ C}$ [1, p. 3-330]. References Haynes, W. M.; Lide, D. R.; Bruno, T. J. CRC Handbook of Chemistry and ...
andselisk's user avatar
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14 votes

Density range of table salt?

The density of $\pu{2.17 g/cm³}$ refers to the density within a crystal of NaCl. In chemical engineering, the terms of powder density, tapped powder density and settled apparent density take into ...
Buttonwood's user avatar
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13 votes

Why is platinum denser than gold?

Since OP is still in the high school, I'll try to explain it simply as possible using mathematical manipulation (hoping OP is more familiar with mathematics than chemistry). Both gold and platinum ...
Mathew Mahindaratne's user avatar
12 votes

What is the least dense liquid under normal conditions?

According to Hans Jaffe: Eine metallische Verbindung von Lithium mit Ammoniak. Elektrische Leitfähigkeit und galvanomagnetische Effekte. Z. Physik 93, 741–761 (1935) https://doi.org/10.1007/...
Karl's user avatar
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11 votes
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Can you theoretically hold more of a volume of water the colder it is?

Water reaches its maximum density at about $\pu{4 ^\circ C}$. As its cooled from higher temperatures the density decreases as you would expect as the molecules move more slowly and they can thus "...
airhuff's user avatar
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11 votes
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Separation of Liquids based on Density

The ability of liquid mixtures to separate is not based on density, but on polarity of each liquid. $\ce{CCl_4}$ and $\ce{C_6H_{14}}$ are both non-polar; they will mix well in solution and not ...
Xahoc's user avatar
  • 918
11 votes

Calculating the theoretical Density of a Lithium oxide

Here's the unit cell of $\ce{Li2O}$, which adopts an antifluorite structure. The image is adapted from this webpage; technically it shows the fluorite structure but it doesn't matter. The cation-...
orthocresol's user avatar
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11 votes

Is the density of a two-component mixture always between the densities of its individual components?

No, there is no law that requires the density of a mixture to fall between the densities of pure components. It does so most of the time, but the exceptions are not unheard of. Here's one. Water: ...
Ivan Neretin's user avatar
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9 votes
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Relationship between molar mass and density in solids

If your sample is solid and crystalline, knowledge of the unit cell's dimension and symmetry (e.g., fcc) and density allows you to determine the molecular mass of your compound. In fact, in ...
Buttonwood's user avatar
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9 votes

My experiemental density of H2 does not match the published data. What causes this discrpenecy?

The pressure inside your balloon is not approximately 1 atmosphere, even at ambient temperature. It is substantially greater, as it has to counteract atmospheric pressure plus the elastic force of the ...
Nicolau Saker Neto's user avatar
8 votes

Why do helium balloons expand in volume as they go higher?

You are exactly correct that it is a matter of atmospheric pressure decreasing at a rate great enough to overcome the contraction due to decrease in temperature. On a nice, clear, dry 25°C day at sea ...
airhuff's user avatar
  • 17.5k
8 votes

Why is the specific gravity of 0.9 % saline 1.0046?

0.9% medical saline is defined to contain $\pu{0.90 g}$ sodium chloride per $\pu{1000 ml}$ solution at $\pu{22 °C}$. Its density is $\pu{1.0046 g/cm^3}$ at $\pu{22 °C}$. The density of water is $\pu{...
aventurin's user avatar
  • 7,230
8 votes

What is the smallest molar volume?

A mole of neutrons in a neutron star would take up about $10^{-20}$ m$^3$. And in a black hole, they would be even smaller.
Acccumulation's user avatar
8 votes
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Why is potassium less dense than sodium?

Although density may be a relatively easily measurable property of solid materials, it may not suggest the most fundamental relationship between mass and volume for the elements. Molar volume (the ...
James Gaidis's user avatar
7 votes
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How to convert from w/w% to molarity?

Weight percent is essentially the same as (I arbitrarily picked grams as the mass unit): $$ \%~\mathrm{w/w~X} = \mathrm{g~X\over g~solution} $$ In order to get to the $\mathrm{mol\over L}$ units of ...
hBy2Py's user avatar
  • 17.4k
7 votes

Can you theoretically hold more of a volume of water the colder it is?

The volume is the amount of space in the container, and no matter what temperature, a liter of water at that temperature occupies one liter. What I think you mean to say is, "Does a liter of cold ...
DrMoishe Pippik's user avatar
7 votes
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Density of moist air

The composition of dry air is about $78\%$ $\ce{N2}$, $21\%$ $\ce{O2}$ and $1\%$ $\ce{Ar}$. The molecular weights of these compounds are: $\ce{N2} = \pu{28 g/mol}$ $\ce{O2} = \pu{32 g/mol}$ $\ce{Ar} =...
airhuff's user avatar
  • 17.5k
7 votes

The definition of density

It depends, there are different kinds of densities: mass density, particle density, charge density, probability density ... Depending on how your measure your matter, mass, number of particles, ...
Feodoran's user avatar
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7 votes

Relationship between molar mass and density in solids

Buttonwood has given an excellent answer with a nice demonstrational video. However, there is one point I'd like to emphasize. In ideal gases, the molar mass is directly proportional to the density: $$...
Mathew Mahindaratne's user avatar
7 votes

Why is potassium less dense than sodium?

Although I liked James Gaidis's answer, I do not agree with some of arguments because they are all parts of one or more continuous trends. For instance, look at the melting points and boiling points ...
Mathew Mahindaratne's user avatar
6 votes
Accepted

What would happen if I mixed a single water molecule in a beaker of hexane?

This is a clever question because the molecular weight of water is only 18.01528 g/mol while the molecular weight of hexane is 86.17536 g/mol. Naturally, you would expect the lower mass to rest on top,...
Ben Welborn's user avatar
  • 1,576
6 votes

Why are most hydrocarbons less dense than water?

There is no truly simple explanation for bulk properties of liquids. But the balance of two factors probably goes a long way to explaining the difference between water and simple hydrocarbons. The ...
matt_black's user avatar
6 votes

Density of moist air

If you considered the air within a given volume in two rooms, one with moist air and one with dry air, moist air will have some water vapor in place of other molecules that make up air (e.g. oxygen ...
J. Ari's user avatar
  • 1,492
6 votes
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Maximum density of heavy water at 11.6 degree Celsius?

The maximum density of $\ce{H2O}$ occurs when cooled to about $\pu{4^oC}$. At this point, the thermal motion of the molecules has slowed down enough such that water molecules can start to orient ...
airhuff's user avatar
  • 17.5k
6 votes

What is the smallest molar volume?

To address you concern about boron, there is a cubic diamond form of boron nitride $\ce{c-BN}$, ICSD #182731 [1], which possesses $V_\mathrm{cell} = \pu{7.99 Å3}$, $Z = 2$ and the molar volume $$V_\...
andselisk's user avatar
  • 38.3k

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