Questions tagged [molecules]
618 questions
183
votes
3 answers
How does a knife cut things at the atomic level?
As the title says. It is common sense that sharp things cut, but how do they work at the atomical level?
wtoh
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140
votes
5 answers
What does it mean for two objects to "touch"?
If you've ever been annoyingly poked by a geek, you might be familiar with the semi-nerdy obnoxious response of
"I'm not actually touching you! The electrons in the atoms of my
skin are just getting really close to yours!"
Expanding on this a…
Thomas Shields
- 1,522
57
votes
3 answers
Are there exact analytical solutions to the electronic states of the hydrogen molecular ion $\mathrm H_2^+$?
The hydrogen molecular ion (a.k.a. dihydrogen cation) $\mathrm H_2^+$ is the simplest possible molecular system, and as such you'd hope to be able to make some leeway in solving it, but it turns out that it's much harder than you'd hope. As it turns…
Emilio Pisanty
- 137,480
38
votes
2 answers
Why isn't the molecule of water linear straight?
When you see models of water you see something like this:
The hydrogens in the water molecule become negatively charged because the oxygen pulls electrons more. So why don't they repel and move to the opposite sides of the oxygen? Or just form on…
Trevor Blythe
- 499
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35
votes
5 answers
Is it heat that causes vibrations on particles or is it the vibrations that causes the heat?
I was taught that molecules move more random when its hot. I am just wondering what really is it that causes something to heat up.
Hunkoys
- 459
34
votes
6 answers
How is water heavier than petrol, even though its molecular weight is less than petrol?
Molecular weight of petrol is so much higher than water,
but when it comes to physical property, weight, one litre of water weighs more than one litre of petrol.
How is it possible?
Olivier Lloris
- 451
32
votes
10 answers
Can a single molecule have a temperature?
A show on the weather channel said that as a water molecule ascends in the atmosphere it cools. Does it make sense to talk about the temperature of a single molecule?
Richardbernstein
- 1,552
30
votes
2 answers
Temperature and time dilation
Say you had some liquid radioactive isotope with a half-life equal to X. If it was cold, the molecules would move slowly, and thus there would be virtually no time dilation involved, resulting in the standard half-life of X.
That same liquid…
Jim Clay
- 537
29
votes
2 answers
In counting degrees of freedom of a linear molecule, why is rotation about the axis not counted?
I was reading about the equipartition theorem and I got the following quotations from my books:
A diatomic molecule like oxygen can rotate about two different axes. But rotation about the axis down the length of the molecule doesn't count. - Daniel…
user36790
26
votes
2 answers
How many molecules rub off when I press a key?
I have a lot of questions below but my overarching questions are: Do surfaces rubbing lightly together always strip molecules off of each other? and How can we model that?
Clearly the answer to the first question is yes in general. We've all seen…
Calvin's Hobbies
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25
votes
1 answer
Why is it so much more energy intensive to compress hydrogen than methane?
Why do you need 13.8 MJ/kg (9% of energy content) to compress hydrogen to 200 bar, but only 1.4 MJ/kg (2.5% of energy content) for methane?
I looked into compressibility factors and the compressibility factor for methane is way lower than for…
24
votes
3 answers
Is it possible to obtain antiwater from antihydrogen and antioxygen atoms? And how is its property w.r.t. the ordinary water?
I am interested in experimental physics and looking for information about the above question.
Dirk
- 361
22
votes
9 answers
Is there such a thing as a "physical" fractal?
The recent discovery of a molecule that mimics the Sierpinski gasket has spurred headlines identifying it as the first fractal scientists have found in nature. I find these claims highly dubious because it's either entirely impossible for a real…
starseed_trooper
- 452
21
votes
6 answers
What is the resonant frequency of liquid water?
I learned it's not 2.45 GHz. But what is it, then? In my failure to find the real value, I'm starting to wonder: does it even make sense talking about a resonant frequency of water molecules?
Wood
- 1,974
20
votes
3 answers
Are water molecules orientation absolutely independent of the flow direction?
Or is there a bias toward a specific angle in regards to the direction of the current?
Winston
- 3,276