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29
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4 answers
How 'heavy' should an element be, to be a "Heavy Metal"?
I've come across the term "Heavy metals" innumerable times in articles, mostly pertaining to environmental issues.
Is there a weight range (of sorts) against which an element (metal) is classified as a "Heavy metal"?
Often I see "Heavy metals" refer…
paracetamol
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29
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Microwaving a glass of water, what happens?
Most of us here would already know the simplified idea behind microwaving food: Microwave radiation hits the water molecules present in food, which excites them and causes 'em to vibrate rapidly in situ resulting in the heating up of food. Very…
paracetamol
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29
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3 answers
Why do salts such as NaCl dissolve?
If we look at solubility of salts in water, we are told that they disassociate, because the positive $\ce{Na}$ ion is attracted to the partially negative oxygen in water and the negative $\ce{Cl}$ is attracted to the partially positive hydrogen.…
Gerard
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29
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2 answers
Why do the alkali metals form different products upon combustion in air?
From Wikipedia's article on sodium:
When burned in dry air, it forms primarily sodium peroxide with some sodium oxide.
We know that sodium has a strong reducing capacity, so why does it produce a compound in which the oxygen atom is not reduced to…
CowperKettle
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29
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Why is −78 °C a magic temperature for organic reactions?
In many organic reactions that I have seen, running the reaction at $\mathrm{-78\ ^\circ C}$ seems to be quite a popular choice, but I've never seen any explanation for this. What makes this temperature such a popular choice?
ringo
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29
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3 answers
Is alcohol really a solution?
A friend recently sent me the following chemistry joke:
As a lover of puns, I'd like to enjoy it, but I think that it is actually false the way it is phrased.
A solution is defined as: "a homogeneous mixture composed of two or more substances"…
JessieArr
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29
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2 answers
Why does fructose reduce Tollen's reagent and Fehling's solution?
Even though fructose is a ketohexose (ketone-containing hexose, a six-carbon monosaccharide), it reduces Tollen's reagent and Fehling's solution. Generally, a ketone does not reduces Tollen's reagent and Fehling's solution. So, why is this possible…
Nilay Ghosh
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29
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3 answers
Why don't gases escape Earth's atmosphere?
Some gases are lighter than others and rise. Why don't they continue going up, leave the atmosphere, and then enter outer space?
S. GOLIZADEH
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29
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1 answer
Are all NO3- salts soluble in water? If so, why?
All the examples of $\ce{NO3-}$ salts are soluble in water (all that I know about).
Is it always so or there is some salt which doesn't dissolve in water?
If so what is the reason behind it?
YAHB
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29
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Does a Grignard reagent react with enones to give the 1,2- or 1,4- product?
Cyclohexenone, an α,β-unsaturated ketone, is electrophilic at both the carbonyl carbon, as well as the β-carbon. So, it can either undergo 1,2-addition to give the allylic alcohol 1, or 1,4-addition to give the ketone 2.
Where does the Grignard…
miyagi_do
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29
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5 answers
Why are tertiary carbocations the most reactive, if they're already stable?
This may seem silly, but doesn't it seem weird for a compound that's stable (in this context, the tertiary carbocation) to be the most reactive?
I mean, wouldn't it be the least, given that it's already stable and wouldn't want to leave that stable…
Yash Chowdhary
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29
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2 answers
Carbocation stability order
I was wondering whether the following order (from here) is correct:
In the first inequality, why did 9 hyperconjugations dominated resonance effect of benzene ring?
In the last inequality doesn't the 2 hyperconjugations of vinylic carbocation…
pikachu
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29
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3 answers
How do you separate enantiomers?
There are some stereochemical reactions that result in the presence of enantiomers. When moving forward with a practical organic synthesis, how does one usually separate them in order to continue with one of the enantiomers?
Cardtrick
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What substances do humans consume that are caloric but neither protein, carb, nor fat?
On the Medical Sciences StackExchange site I asked Can a calorie be neither protein, carb, nor fat?
and got a very helpful answer, which was that ethanol (in alcoholic drinks) is caloric but neither a protein, nor a carb, nor a fat. I then asked a…
Nathan Wailes
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2 answers
How to properly store acids at home?
I bought different kinds of acid for experiments and home usage that I stored in secured containers into an IKEA cabinet.
I just realized that despite the fact that all the containers are properly closed, the metal parts of the cabinets are…
nowox
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