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1500 questions
16
votes
2 answers
Why does graphite have a high melting point even though its intermolecular forces are weak?
From what I've read online, when a substance undergoes a state change, the intermolecular forces are broken. The covalent bonds are not broken (http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_pre_2011/chemicals/airmolecularrev2.shtml)
My…
Christopher U
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16
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6 answers
How to determine the most stable carbanion?
Which of the following carbanions is the most stable?
I think the answer is either a or c, as in d there are no chances for the carbanion to have its charge become less. In b I think there is a + inductive effect due to methyl group which gives…
Adesh
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16
votes
2 answers
Francium has isotopes so how can its atomic mass be a whole number?
Why do francium, radon, radium, and actinium have whole numbers for average atomic mass even though they have isotopes? But then elements like beryllium, fluorine, and sodium are listed as having no isotopes but yet they have a decimal for their…
M Floehr
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16
votes
4 answers
What is the strongest oxidising agent?
I searched for the strongest oxidising agent and I found different results: $\ce{ClF3}$, $\ce{HArF}$, $\ce{F2}$ were among them.
Many said $\ce{ClF3}$ is the most powerful as it oxidises everything, even asbestos, sand, concrete, and can set easily…
Harsh jain
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15
votes
2 answers
Flame test: Is the metal atom or the metal ion responsible for the flame colour?
A sample of $\ce{CaCl2}$ is placed in the flame of a Bunsen burner. The component of the substance which is responsible for the production of the flame colour is:
$\ce{Ca^2+}$
$\ce{Ca}$
$\ce{Cl-}$
$\ce{Cl}$
Why is the textbook answer $\ce{Ca}$…
confused
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15
votes
1 answer
Does the chemical in an alkaline battery make battery leaks unavoidable?
Battery leaks was an issue in the 80s and 90s, and since quality and innovation is constantly improving, I thought battery leak might be slowly going away. But I found that even nowadays, name brand alkaline batteries still leak after a while, even…
nonopolarity
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15
votes
7 answers
If the human body consists of 60% water why can't we put out fire with our body?
I have often heard of people being burned at the stake, but if the body is 60% water shouldn't the fire just be put out?
ArnavT
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15
votes
3 answers
What to do with (large) imaginary frequencies for constrained minimum structures?
I am performing DFT calculations using ORCA 4.0.1 on an enzyme active site model. The model contains 89 atoms including the substrate (see Animation 1), five of which are fixed in space (the spherical atoms in Animation 1). I am using…
Yoda
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15
votes
2 answers
Are atoms really round?
I'm not sure if this is a silly question, but I was sitting here with a cup full of cheezey poof balls thinking, "My goodness, it's like an amazing cheesey delicious liquid - huge water molecules!"
Of course my next thought was, "Wait a minute -…
Wayne Werner
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15
votes
1 answer
Can a zeroth order reaction be reversible?
After recently studying about chemical equilibrium, I was convinced that the forward and backward reaction rates meet each other at equilibrium.
However thinking about zeroth order reaction annoyed me a little, as I could not figure out how the…
Gamma-1-X-Ray
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15
votes
1 answer
Why only two atoms share an electron and not three?
In a covalent bond between two atoms, an electron from one of the either atom is shared by overlapping of their orbitals.
So,
Why can't three atoms share an electron and overlap their orbitals?
user3459110
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15
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2 answers
Does the pre-exponential factor (Arrhenius constant) depend on temperature?
I was taught that the the pre-exponential factor $A$ in the Arrhenius equation \eqref{arrhenius} does not increase with temperature.
$$k = A\cdot\mathrm \exp\left(-\frac{E_\mathrm a}{RT}\right)\tag1\label{arrhenius}$$
But, a component of the…
Mick
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15
votes
4 answers
Mismatch of plane of symmetry vs Gold Book's definition for a pseudochiral carbon
Here is pentane-2,3,4-triol:
At first glance, without deciding the configurations at each chiral carbon, we can clearly see that this molecule has a plane of symmetry, perpendicular to the plane of paper and passing through the $\ce{-OH}$ and…
Gaurang Tandon
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15
votes
1 answer
Reaction of phenol with Zinc dust
I have seen this reaction many times:
$\text {Phenol}+\text{Zn}\ce {->}\text{Benzene}+\text{ZnO} $
But what is the mechanism?! Tried a lot but couldn't cook up one...
Thanks for any help...
Apurv
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15
votes
2 answers
Le Chatelier's principle: Are there any exceptions?
The way Le Chatelier's principle is presented in most introductory chemistry books (high-school) is as though it's an indisputable law of the physical world (in the sense that we're never shown an exception, not that its universality is explicitly…
paracetamol
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