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1500 questions
18
votes
3 answers
What causes the smell in rotten meat-grease and how can I get rid of it thoroughly?
We've just spilled the can of used meat-grease we collect so that it doesn't go down the drain and it turns out it was rotten. Now the granite counter-top and the wood-laminate floor of the kitchen smell very bad even after repeated cleaning with…
Daniel Miles
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18
votes
3 answers
Is there any special rules for checking the aromaticity of polycyclic compounds?
This question arose in my mind because it's given in a book that pyrene is aromatic. How can it be with 16 π electrons? So, it should be actually anti-aromatic or is there any special rule for these types of compounds?
Rajath Radhakrishnan
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18
votes
7 answers
What exactly is a mole?
Upon coming back to University I've started studying basic chemistry again. I've always had trouble with the concept of "moles". According to my study book,
1 mole of any element or compound is equal to its molecular weight in
grams.
I…
teachmechemistry
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18
votes
2 answers
Gauche effect and bond length
Which of the following compounds has the longest bond length?
(A) $\ce{H3C-CF3}$
(B) $\ce{FCH2-CH2F}$
(C) $\ce{F2CH-CHF2}$
(D) $\ce{F3C-CF3}$
My logic was based on the relative electronegativities of the two carbons. The more fluorines there are…
Sanika Khadkikar
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18
votes
3 answers
Where does the label ‘Dq’ to denote the field split in coordination compounds come from?
As established in a previous question, coordination compounds typically have a field split between the $\mathrm{t_{2g}}$ and the $\mathrm{e_g}$ d-orbitals.[1] This energy difference can be explained by the crystal field theory which assumes negative…
Jan
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18
votes
2 answers
What does a number in brackets after another number mean? I.e. 21(1)cm-1
What does the number in brackets mean in these two examples?
$$21(1)\ \mathrm{cm^{-1}}$$
and
$$1.0(3)\times10^{-7}$$
draksi
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18
votes
3 answers
Do Electrons Really 'Spin'?
With regard to the 'Electron Spin Number', lots of websites mention that electrons don't really spin and that the electron spin number has nothing to do with any physical spinning.
However, my chemistry teacher is quite adamant about electrons…
paracetamol
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18
votes
2 answers
Why are fluorides more reactive in nucleophilic aromatic substitutions than bromides?
In nucleophilic aromatic substitution reactions, why do fluorides react faster than bromides?
Ordinarily bromide is a better leaving group than fluoride, e.g. in $\mathrm{S_N2}$ reactions, so why isn't this the case here? The only thing I can think…
Preeteshwar
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18
votes
1 answer
Why is acetone so cold?
I have a summer job as a custodian and one cleaner I use is called Goof Off, which is pretty much just acetone. Another is a disinfectant which is mostly water.
Why is it that whenever I put the acetone on my rag, it is always colder than when I use…
Ryan
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18
votes
1 answer
Unknown glassware
I recently found a piece of older glassware in our lab and nobody seems to know what it is. It appears to be some sort of condenser; however, it does not have both the in and out little notches on it.
It is open on both ends and has one smaller…
skennedy
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18
votes
2 answers
(Computationally) finding similarity between two organic compounds
I have been struggling to find an acceptable answer for this question for my purposes.
There are many ways to find similarity between two organic compounds - some of which are particularly popular in chemoinformatics. The seemingly most popular way…
kosyumote
- 381
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18
votes
2 answers
Why is a theoretical titration curve higher than a practical one?
I'm currently in high school and I did two titrations. The first one is a titration of $10.0~\mathrm{mL}$ $0.1~\mathrm{M}$ $\ce{HCl}$ with $x~\mathrm{mL}$ $\ce{NaOH}$. I obtained the following titration curve:
The blue curve is what I measured and…
Tim Vermeulen
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18
votes
1 answer
Counterintuitive Reaction of Aluminium On Steel Balls
There is a certain video which I just watched about 2 large cast iron balls. If the balls are struck together, no reaction happens, but if one is covered in aluminium foil and then struck, a large quantity of sparks are produced. This flies in the…
Sarah Szabo
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18
votes
3 answers
What is the formally correct notation of t-Bu, i-Pr, p-NO2, n-Bu, a-HCl, etc.?
In chemical notation, can I safely assume that the notation of
a single lower-case latin character
followed by a hyphen
followed by an Element upper-case latin character (and possibly more characters)
should always be typeset as
italic lower-case…
mhchem
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18
votes
2 answers
Hydrogen bonding in staggered vs eclipsed conformations
In my first semester of organic chemistry, we learned that staggered conformations have lower energy/higher stability.
However, my thought is that if you have interacting OH groups, the hydrogen bonding would make the eclipsed conformations more…
Melanie Shebel
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- 86