Questions tagged [density]

For questions involving (theoretical or experimental) comparison of density of elements or substances, calculating density of solutions, effects of temperature on density, and other chemical aspects of density.

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37
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6answers
62k views

Why do we use helium in balloons?

While I was looking at the periodic table today, I realised that there were gases that were much lighter than helium such as hydrogen. If hydrogen is lighter than helium, why do we insist on using ...
24
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3answers
12k views

Which is the densest gas known?

Which is the densest gas known to exist under normal "shirt sleeve" conditions: room temperature, one atmosphere, won't explode on contact with air, won't kill everyone in the building in trace ...
13
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3answers
7k views

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

I realize as balloons go higher, the atmospheric pressure decreases, doing less to counteract the force of the gas particles pushing against the inner walls of the balloon. But at the same time, doesn'...
13
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1answer
2k views

What is the least dense liquid under normal conditions?

What is the least dense liquid under normal conditions, room temperature, one atmosphere of pressure, doesn't combust upon contact with air, also wouldn't kill a human just for being in the same room ...
12
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4answers
1k views

What is the smallest molar volume?

I wondered how small a volume a mole of material could occupy, so I started with carbon, which would need 12 grams. That's 60 carats, and there happens to be a famous 60 carat diamond. If my density/...
11
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1answer
604 views

What are these “certain chemical compounds” denser than osmium?

The Wikipedia entry for density states Osmium and iridium are the densest known elements at standard conditions for temperature and pressure but certain chemical compounds may be denser. I ...
9
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1answer
5k views

Are there any gases more dense than liquids?

Inspired by Is there any type of liquid, other than mercury, that PTFE teflon is known to "float" to the surface in?, are there gases that are more dense than liquids? (So bubbles would sink ...
8
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1answer
3k views

Calculating the theoretical Density of a Lithium oxide

I am trying to calculate the theoretical density for lithium oxide using the following formula $$\rho= \frac{n^{'}\sum M_c+\sum M_A}{V_c N_{AV}}$$ where $n^{'}$ is the number of formula units in unit ...
7
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3answers
8k views

Would equal masses of gold and copper result in the same volume change if added to water?

Would equal masses of gold and copper result in the same volume change if added to water? Density of gold: $19.3~\mathrm{g/mL}$ Density of copper: $8.96~\mathrm{g/mL}$ I was thinking the answer ...
7
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4answers
1k views

Causing a metal or glass marble to float in an aqueous solution

I am trying to find a way that you could cause metal (Aluminum) or glass to float in a mixture of water and some water-soluble material. I am aware that salt can be used to heighten the density of ...
7
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1answer
607 views

Misconception? “That gas is heavier so it sinks.”

I've heard people say many times that one gas is heavier than the other so the heavier gas sinks. Now this must certainly be true to a certain extent (I think of gas used in WWI that sunk into ...
6
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2answers
4k views

How can the density of water be maximised?

What is the maximum possible density of water at room temperature? The density of the water in the Dead Sea at 37°C is 1.24. Would it be possible to increase the density using salts we add to our food,...
6
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1answer
5k views

Calculating the volume of 1 mole of liquid water

I am doing some rough calculations to test my understanding of elementary chemistry. In what follows, I calculate the volume of one mole of liquid water at about $\pu{4 ^\circ C}$ and $\pu{1 atm}$: ...
5
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1answer
5k views

How can molecular mass be calculated from vapour density?

An organic compound contains 71.7% carbon, 6.7% hydrogen, 10.4% nitrogen and 11.8% oxygen by mass. Given that its vapour density is 67.5, determine its empirical formula and molecular formula. From ...
5
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1answer
35 views

How to make equal density pool dye without diffusion

I have a leak I have been struggling to find in my in-ground pool. I am losing about 1/4" of water per day and I believe the issue is one of the fittings in the bottom of the pool. There are two ...
5
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3answers
984 views

Calculating the density of a saturated salt solution

Is there a way to calculate the density of a saturated salt solution from the solubility limits or does it have to be experimentally determined? First instinct, is to add the mass of the salt to ...
5
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1answer
107 views

Specific gravity of H2O2 bleached viscose [closed]

What is the specific gravity of $\ce{H2O2}$ bleached viscose? In literature, I can find that this is $1.52~\mathrm{g~cm^{-3}}$, but for bleached viscose is it not findable. Can I presume $\ce{H2O2}$ ...
5
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0answers
37 views

Why are the OV and VO blocks of the CIS 1RDM zero?

I know the reduced density matrix has the form: $$ \gamma(\alpha,\beta) = \langle\Psi_N|c^{\dagger}_{\alpha} c_{\beta}|\Psi_n \rangle $$ but when $\Psi_N$ is the configuration interaction singles (CIS)...
5
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4answers
1k views

Does a freezing point of a substance always increase as its boiling point increases?

I am studying for an introductory to physical sciences test and came upon a chart describing substances found in petroleum and the distillation process. Each freezing point increases as each boiling ...
4
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4answers
2k views

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

I have basic knowledge of chemistry and how it all works (will be taking the class next year) but I understand density and mass. Since the hotter a liquid, in this case, the molecules are more ...
4
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3answers
218 views

Two liquids that react to produce a gas less dense than air at room temperature

Does anybody know two liquids (or a solid and a liquid) that can react to produce a gas less dense than air (or similar) at room temperature? This question is intended to make a chemical induced ...
4
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1answer
853 views

Separation of Liquids based on Density

I was doing some practice problems when I came across this one The answer key says the answer is B but I don't know why. Isn't the difference in the molar masses of the two substances in D greater ...
4
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3answers
1k views

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

What would happen if I mixed a single water molecule in a beaker of hexane? Would it sink or float? How about 2 water molecules? 3? Etc? In other words, how many water molecules does it take to be ...
4
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1answer
401 views

Determine balloon diameter needed to lift a 7 pound weight with various gases

My question is regarding setting up this equation. The givens are as follows: Gases are helium, methane and hydrogen. (Test all three) Assume balloon is spherical. Assume temperature is $25~\mathrm{^\...
4
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1answer
7k views

Density and solubility

Do all saturated solutions have the same density? Based on your data, which salt is more soluble? \begin{align} &\ce{NaCl} & \pu{11.812 g/10 mL} \quad &\text{or} \quad \pu{1.181 g/...
3
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2answers
818 views

Density of moist air

Why does moist air have lesser density than dry air? When the amount of vapor inside increases, the mass increases and hence won't the density as well increase?
3
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2answers
3k views

Mass of salt required to make a 1.2 g/ml solution

I would like to make an NaCl and water solution with a density of 1.2 g/ml. How would you calculate the grams of NaCl required to make a 1000 ml solution? I have used density of mixture = (mass NaCl +...
3
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1answer
79 views

Density of cyclic hydrocarbons

Why is the density of cyclic hydrocarbons more than that of their acyclic counterparts? For ex: ...
3
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1answer
338 views

Multiphasic liquid “flotation” experiment

I'm trying to create an experiment where two immiscible liquids are mixed and are then separated by density. Most of the container is occupied by the lighter liquid, and the small amount of heavier ...
3
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0answers
35 views

What gas would be suited best to form a density gradient in a long tube? [closed]

I want to set up an aero-optics experiment using a sealed ~5 m length of pipe with a gas inside. The gas must form a density gradient, and must be transparent enough to view a target at the other end ...
3
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1answer
65 views

Why are chemistry droppers bad at holding bromine? [closed]

Question in my chemistry test last week. The question was related to a previous question on bromine's density.
3
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0answers
53 views

Specify the formula of the product X_n Y_m [closed]

During a chemical reaction, equal moles of two diatomic molecules $\ce{X}$ and $\ce{Y}$ are allowed to react to form one gaseous compound $\ce{X_nY_m}$. After the reaction is complete, it was observed ...
3
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1answer
583 views

Why is methyl iodide more dense than ethyl iodide, even though the latter has more carbon atoms?

It is understood that more carbon atoms present in a hydrocarbon, the greater the density of the hydrocarbon. But then why does $\mathrm{CH_{3}I}$ have a greater density than $\mathrm{C_{2}H_{5}I}$?
3
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2answers
1k views

Most energy-dense commercial battery available

What's the most energy-dense and currently commercially available chemical battery technology? Would it be the Lithium-Ion Polymer or has it been surpassed already? There's is a chemical non-...
2
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1answer
1k views

How can I interpolate between two densities at different temperatures?

I'm trying to find the temperature of methanol ($\ce{CH3OH}$) when its density is equal to $\pu{780 kg m-3}$. I know that when $T = \pu{30^\circ C}$ the density is equal to $\pu{783 kg m-3}$, and ...
2
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1answer
118 views

The definition of density

Could density be defined as the measure of matter per unit volume instead of mass per unit volume because mass is a measurement of matter?
2
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1answer
2k views

Maximum density of heavy water at 11.6 degree Celsius?

I came across a question asking me the temperature at which $\ce{D2O}$ will have maximum density. I didn't really know, so I checked the answer, and I found that the answer is $\pu{11.6^oC}$. But why ?...
2
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6answers
5k views

Why is the specific gravity of 0.9 % saline 1.0046?

Medical Normal Saline (0.9% Saline) contains 9 g of salt dissolved in 1000ml of water. Hence a litre of NS should weigh 1.009 kg. Hence its specific gravity should be 1.009, but it’s only 1.0046. (I'...
2
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1answer
783 views

Correction formula for alcoholmeter

I need to find the formula, if there is one, which would calculate the correction of alcoholmeter. Basically convert observed %ABV (Alcohol by volume) to actual %ABV using the sample's temperature. ...
2
votes
1answer
193 views

Density of water and temperature

Is there a formula that shows how the density of water is affected by temperature? For example, with the speed of sound it can be shown how temperature will affect the speed: $$V = 331\ \mathrm{m/...
2
votes
2answers
850 views

Density of d-block elements

Something that confuses me slightly is the trends in density when comparing periods 4, 5, and 6 in the d-block. Looking at periods 5 and 6, the density peaks at group 8, with ruthenium and osmium, ...
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1answer
1k views

Water and olive oil intereactions

This is really basic knowledge, but I am a little confused. I understand that if you put a tablespoon of water and a tablespoon of olive oil in the same container the water descends at the bottom of ...
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3answers
45k views

How to convert from w/w% to molarity?

After reading a number of explanations about it after googling, I'm a bit confused on this. Some explanations are doing it using a solution density, others aren't, though most are. On one site it's ...
1
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2answers
68 views

Finding percentage of the gas in a binary gaseous mixture of the given density

At STP, the density of a gas in a vessel is $0.9002$. If the gas is a mixture of argon and helium, what percentage of the gas is argon? I am stuck on this. From what I can gather, the only ...
1
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1answer
265 views

How would one make a non-toxic pen out of osmium?

Osmium is the densest element in the periodic table. However, it is toxic in its pure form. Is there a way to create a standard pen out of osmium but coat it in a dense material that isn't toxic to ...
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1answer
5k views

What is the boiling point and density of LSD?

I have tried to do a lot of research and didn't succeed to find the boiling point and density of LSD. I would want to know this information. In addition, I can't use Clausius–Clapeyron equation ...
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1answer
4k views

How do I calculate the density of propane assuming an ideal gas?

Assuming an ideal gas, calculate the density in $\mathrm{g/cm^3}$ of propane, $\ce{C3H8}$ at $0.000~^\circ\mathrm{C}$ and $1.000~\mathrm{atm}$. (3 significant figures) I have figured out that I need ...
1
vote
1answer
91 views

What is the mathematical relation for the change in water density at different temperatures?

I am curious to the relation of the density of water at different temperature and as to also how one would come to an equation that took the temperature of the water and would output it's density? I ...
1
vote
1answer
375 views

Isotopic mass to density

I want to figure out/calculate the density ($\pu{g/cm3}$) of the various isotopes, here $\ce{^109Ag}$. I know it's isotopic mass is $\approx109$ and calculated the number of particles/gram. But I ...
1
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1answer
753 views

Conversion of grams to milliliters using kg/m3 density

Convert 100 grams of a solution to milliliters with a density of $681.9\rm~\frac{kg}{m3}$. It also has a density of 5.69 pounds per gallon. Are any or all of these correct? $$\rm100~g \times \frac{...