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1500 questions
18
votes
2 answers
Can we really see the bonds?
I was thinking is there really bond present at microscopic level or atoms/molecules are just nearby and are connected with force which is not visible(like gravitational force between earth and sun) and we make bonds just for understanding.
Freddy
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18
votes
2 answers
Why doesn't HCl form when you dissolve NaCl in water?
People say it dissolves, but shouldn't the acid form?
$$
\ce{NaCl + H2O ->[?] HCl + ???}
$$
Asker123
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18
votes
1 answer
Why six C atoms are usually seen in cyclic compounds?
When it gets to Carbon-based molecules, one very possible structure when there are more than six C atoms is the hexagon; though not mostly perfect, it emphasizes that six Carbon atoms tend to bond with each other.* Why?
I assume this is because of…
M.A.R.
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18
votes
2 answers
How should the hydrated proton be represented in chemical equations?
I learned the equation
$$\ce{H2O + H+ -> H3O+}$$
And I know $\ce{H+}$ and $\ce{H3O+}$ really mean the same thing. But I am confused as to when I should use $\ce{H+}$ and when I should use $\ce{H3O+}$? Is any one of them a more accurate…
Simon-Nail-It
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18
votes
4 answers
What possibilities are there for refining aluminium on the moon?
Engines burning aluminium and liquid oxygen have been investigated for use on the moon because there is plenty of both elements in the soil - about 13% and 40% of highland soil, respectively. Propellant thus has the potential to be sourced from the…
kim holder
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18
votes
4 answers
Reason for inability to find the absolute value of internal energy
Today in my thermodynamics lecture, my teacher told me that it is not possible to find the absolute value of internal energy and so we have to calculate the change in internal energy.
So, my question is why isn't it possible to find the absolute…
Freddy
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18
votes
1 answer
How does H2O2 bond
I am asking this question on behalf of my seven year old daughter, so if possible please take that into consideration in the answer!
I am not a chemist, but I do try to teach my daughter the basics of diverse subjects. I explained to her that the…
dotancohen
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18
votes
1 answer
Interpretation of TD-DFT results
For the first time I'm doing TD-DFT calculations (wB97XD functional) in Gaussian 09 for an open-shell system and the results look like the hell of a mess for me. The molecule is rather big, so I started with just 10 excited states to see how it…
Wildcat
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18
votes
2 answers
Why are some pH standard solutions 6.86 and 9.18?
I have calibrated pH sensors in the lab on several occasions and have used standards of 4.0, 7.0 and 10.0 usually. Recently I received a sensor and was tasked to calibrate it, but it requested standards of 6.86 and 9.18 in addition to the 4.0 — with…
en_lorithai
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18
votes
5 answers
How to dissolve candle wax (paraffin)?
Wikipedia states that waxes can be dissolved by non-polar organic solvents.
I failed to dissolve candle wax in both acetone and ethanol, which are the only organic solvents I have at home.
I have some clothes with wax stuck on them. How can I…
Tomáš Zato
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18
votes
1 answer
Stability of organophosphorous vs organophosphates?
In environmental chemistry, most of the organophosphorous compounds we worry about are actually organophosphate compounds.
Is there something about the $\ce{C-P}$ bond that makes it less stable (and thus less persistent in the environment) than a…
Pat
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18
votes
2 answers
Dipole moment of cis-2-butene
I need someone to back me up on this before I go confront my teacher:
I was doing some analysis of the dipole moment of cis-2-butene.
Let's say that the alkyl groups are both on top.
Would the dipole moment be a vector that has its tail on the top…
yolo123
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18
votes
3 answers
What is going on in and below a yellow or blue gas flame?
Unsure if this is more chemistry or physics, but here goes...
Consider a Bunsen burner and the flame it produces when the air inlets are closed vs open.
According to the description on the linked Wikipedia page, combustion is incomplete when the air…
Anthony X
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18
votes
1 answer
Linear algebra and Hess's law?
I am a high school student taking chemistry who was tasked to solve a large set of Hess's Law problems. Naturally I tried to find a way to get my computer to carry out this repetitive piece of work for me.
I tried to model the problem mathematically…
user104941
18
votes
2 answers
Why does a 57.15% ABV spirit (ethanol+water) have a density of 923 kg per cubic meter?
According to the UK proof standard, a 100 proof spirit was defined as a spirit with gravity of $\frac{12}{13}$ that of water or $\pu{923 kg m-3}$, which is equivalent to $\mathrm{57.15\% \ ABV}$.
One liter of $\mathrm{57.15\% \ ABV}$ spirit…
effmate
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