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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110 views

When finding the liquid density which gives the most accurate results, a 25 ml Pycnometer or a graduated 10 ml cylinder?

Its 10 ml graduated cylinder with 25 ml of pycnometer, and we are measuring the density of the liquid(pure liquid) in each of the materials and we are suppose to compare the densities found , in terms ...
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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 ...
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0answers
50 views

Theoretically predict the density of water

Is it possible to predict the density of water having just its molecular structure (basically obtain 1 g/cm3 at 3.96 °C)? Are you aware of research/textbook that dive into this topic? Is it able to ...
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2answers
831 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, ...
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 ...
11
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1answer
596 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 ...
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1answer
903 views

How to formally calculate the surface density of layered materials such as graphene?

Typically density is defined in units of mass per volume. In the case of graphene it is mass per area, i.e. surface density. What would be the correct way to calculate the surface density (mass per ...
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)...
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 ...
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0answers
56 views

Predicting atomic weight and density of calcium [closed]

I have a question from school: Assuming that the element Ca had not been discovered, predict using the properties of the known element surrounding Ca its own properties such as its atomic weight ...
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2answers
100 views

Density and concentration of hydroiodic acid [closed]

I weighted my hydroiodic acid sample: 25 ml weight 34.1 g, so the density is about 1.364 g/ml. I want to know its concentration based on density. Does anyone have the corresponding density chart?
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1answer
77 views

Most dense hydrogen containing composition [closed]

I am searching for a composition which could host the most hydrogen atoms in a specific volume. Note that this density is sought for justifiable conditions in terms of pressure, temperature, ... and ...
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1answer
108 views

Why doesn't the density of water add up? [closed]

If the density of hydrogen is 0.09 g/ml and the density of oxygen is 1.429 g/ml, how is it that the density of water is 1 g/ml?
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0answers
53 views

Over time what happens to soluble liquids with different densities

I have a case with two liquids: Water and another chemical which is miscible in water. The chemical has a density of 800 g/l so it's 20% less dense than water. Initially the chemical was mixed with ...
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0answers
27 views

Two common fluids that don't mix inside a labyrinth [closed]

I'm not sure in which SE site put this question. Imagine a typical child toy, where a bunch of spheres move by gravity through a labyrinth. Now imagine a sealed small labyrinth with two fluids. I'd ...
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1answer
108 views

What Value of Purity Do We Substitute in the Formula C=10PD/M

In the the formula $$C = 10P\frac{D}{M}$$ $C$ is the concentration of a substance in a solution, $P$ is the percent concentration (purity) of the substance, $D$ is the relative density of the ...
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1answer
33 views

Sample: How to calculate mass of nanopaticles with given density and Vol % [closed]

I'm trying to calculate the wt% and the mass of the nanoparticles in a ferrofluid solution. Attached is data from the supplier: ...
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2answers
230 views

How to reduce surface tension of oil?

I would like to create tiny colored drops slowly falling down in a transparent liquid. The diameter of the droplets must be around 2mm, and their speed must be approximately 0.5 mm / sec. For that, ...
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1answer
96 views

How to make oil more heavy?

I would like to increase the density of a given oil (or anything that repels water) so that it is slightly heavier than water; to be able to precisely control how slow the oil would fall in the water. ...
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1answer
39 views

Concentration of electrons in silicon sample with a phosphorus dopant

I'm studying electrical and computer engineering and all I remember from chemistry is from high school. We have a $\ce{Si}$ sample and we want to replace one in every million atoms with a phosphorus ...
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 ...
5
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3answers
977 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 ...
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1answer
1k views

What is the density of compressed natural gas (CNG) used in vehicles? [closed]

I would like to know the density of the compressed natural gas used for natural gas vehicles in order to complete the formula in this Mathematics Stack Exchange post.
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0answers
22 views

Calculating Air Density and Effect of Air Composition

I have to calculate density of atmosphere, assuming that it is: 79% : N2 21% : O2 Does the percentage of gases affect the answer, and how can we find the density with such little information?
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1answer
133 views

Does iron nail sink in rubbing alcohol [closed]

I have been trying for so long to get answer
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0answers
43 views

Determine Which has the higher density the pure liquids or solutions?

What i know that it immensely depends on their individual density, but am not really sure since doing research they was no solid answer. i just want a conformation if what am suggesting is correct.
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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/...
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1answer
774 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. ...
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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 ...
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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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 ...
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3answers
12k views

How does density of alkali metals increase down the group?

Size of alkali metals increases down the group, so volume also shows increment, and since volume is inversely proportional to density, how does density also increase down the group?
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1answer
68 views

How to determine the volume of water necessary to produce a solution with 4.9 g/l sulfuric acid?

The molar mass of sulfuric acid is $M(\ce{H2SO4}) = \pu{98.1 g/mol}$. We have $\pu{100 mL}$ of a $0.1$ molar solution of sulfuric acid. What volume $V$ in $\mathrm{mL}$ of water, $\ce{H2O}$, do we ...
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1answer
44 views

How to calculate the average size of cubic crystals of KCl powder? [closed]

The total area of $\pu{0.5 g}$ sample of $\ce{KCl}$ powder is measured to be $\pu{1620 cm2}$. If the powder consists of tiny cubic crystals, what is the average size of these crystals? I'm studying ...
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0answers
84 views

What is the actual density of CAS 7647-14-5 (NaCl, 99+%)?

I'm not a chemist by profession, so please forgive any syntactical or vernacular oversights on my part. Basically, I'm getting mixed messages from different sites about the density of sodium chloride....
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 $\pu{1 atm}$: ...
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'...
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1answer
558 views

How to find the volume of ice given its density, and the volume and density of water used? [closed]

Just trying to understand density calculations, for example, Water has a density of $\pu{0.997 g cm^-3}$ at $\pu{25 ^\circ C}$; ice has a density of $\pu{0.917 g cm^-3}$ at $\pu{-10 ^\circ C}$. If a ...
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 ...
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1answer
372 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 ...
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0answers
388 views

Find alloy composition by density

I have a square piece of metal from a processor heat sink that looks a lot like copper. I'm trying to find the alloy composition but I'm not sure how. I happen to have both a digital caliper and a ...
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1answer
47 views

Is there a formula for density of any gaseous substance just based on its molar mass?

$\pu{112 ml}$ of hydrogen combines with $\pu{56 mL}$ of oxygen to form water. When $\pu{224 mL}$ of hydrogen is passed over heated cupric oxide, the cupric oxide loses $\pu{0.160 g}$ of its weight. ...
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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'...
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0answers
187 views

Electron Probability Density Functions

I am a mathematics and chemistry double major and I just finished my statistics requirement and a great deal of the class was spent on probability distributions (e.g. Binomial, Poisson, Geometric, ...
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2answers
137 views

Density of plutonium oxide

I am trying to find the mass density $\rho$ of plutonium dioxide, $\ce{PuO2}$. I could calculate it, but the mass density of oxygen found in the literature is the density of gas oxygen. So I was ...
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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 ...
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0answers
183 views

What's the density of a frozen ethanol or ethanol solutions?

How can we know what's the density of ice (water), but there's no data on how much is the density of frozen ethanol? (as far as I know)
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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{^\...
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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 ...
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1answer
4k views

Find the number of copper spheres in a box

A box contains a mixture of small copper spheres and small lead spheres. The total volume of both metals is measured by the displacement of water to be $\pu{420 cm^3}$ and the total mass is $\pu{5.4 ...