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.

19 questions with no upvoted or accepted answers
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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)...
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0answers
103 views

What are the least dense fluids?

This question left me wondering what other very light (condensed) fluids could exist, at any environmental condition. Obvious candidates for the list are (at their Bp./1 bar) LH2 (0.07 g/ml) LHe (0....
3
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1answer
795 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 $\mathrm{C_{2}H_{5}I}$?
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2answers
2k 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, ...
2
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1answer
50 views

Density of water increases from 273 to 277 K due to increase in entropy?

In a set of questions that I was solving, the answer to one of the questions asking why the density of liquid water increases from 0 to 4 degrees C had the above answer: due to an increase in entropy. ...
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0answers
92 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
24 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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0answers
85 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....
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0answers
507 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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0answers
226 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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0answers
238 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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0answers
105 views

Why does increasing electronegativity difference result in decreasing density?

I've been collecting data and there's a very strong inverse relationship between electronegativity difference and density ($\pu{R^2}$ value of roughly 0.95 from my data). Is there any chemistry that ...
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0answers
199 views

How is density “predicted”?

Hassium is predicted to be the densest element at 41 g/cm ^3, but how do you predict something like that? Wikipedia says there have only been 100 hassium atoms made to date and it's half life is less ...
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35 views

What's causing my energy calculations to be wrong?

I'm calculating the energy density of certain flammable compounds in MJ/kg. To do this I compare the sum of the bond strengths of the reactants to the products and then extrapolate the energy density ...
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0answers
53 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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129 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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0answers
105 views

What causes mercury to expand equaly unregarded what the temperature increase is?

Mercury seemed to be a good liquid to use in thermometers. But why are most liquids expanding non-linearly with increase of temperature compared to other liquids?
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25 views

Relating to density trend of alkali metals

Why is the density of potassium less than that of sodium? And why doesn't it follow the trend of increasing density down the group?
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3answers
14k 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?