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Small Qs and As about chemistry

Survival0200

Survival0200

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I decided to make a topic where people could ask small questions about chemistry. Questions that are too small to make a topic about, but still something you'd like to know. Just if it's okay to moderators to make this kind of topic. :)

So, maybe I'll start then:

When making a substance from synthesis is it called synthesizing or just 'making'?
 
"Making" is a very general term. When applied to chemistry, synthesis is a somewhat more specific term.

First link from a google search using terms: synthesis and definition

1. In chemistry, the formation of a compound from simpler compounds or elements. 2. The production of a substance (eg, as in protein synthesis) by the union of chemical elements, groups or simpler compounds, or by the degradation (ie, breaking down) of a complex compound.
Click to expand...


I'm not sure such a thread is a wise move considering forum guidelines.
 
Well, here it is without the math, if this is what you were looking for. Very brief overview of it (quantum numbers were not my speciality.)


The Pauli Exclusion Principal, in a nutshell, states that no two electrons can have the same quantum numbers. So if you already have two atoms with the same N value there L, M, and S values must be different. So when you're filling in an electron chart, you have to remember that "Oh, I already have two with the same N, L and M values, their S values have to be different!"

And what's so bad about the thread? I make lots of stuff at home in my ghetto chem lab, none of which is illegal. Just because one can apply this knowledge to making illicit materials, does not mean that it's so much against forum guidelines as it's not asking "how do I make meth"

And can someone give me a brief rundown on oxidation numbers and why they turn different colors? My chem class kinda skipped right by this and I thought it was cool...but I had to hand in my chem book, which meant I couldn't work it out over the summer.
 
Okay, I got into an arguement with someone. I don't know a lot about chemistry, but I'm sure I'm right. He has a PhD is plant-extract pharmacology (including the chemistry) so he should be right.

Anyway, he says, long chain primary alcohols are more polar that short ones, i.e. butanol is more polar than methanol.

I say that is rubbish because more carbons can donate more electrons to the oxygen, reducing the polarity, and of course long chain alcohols don't disolve in water (where do they stop? Pentanol?) Thanks.
 
From my organic textbook, water solubility of 1-3 carbon straight chain alcohols is infinite; n-butanol is 8.3 g/100ml, and n-pentanol is 2.4. Anything longer than that is basically insoluble.
I'm pretty sure you're right, but I don't have any information off hand about dielectric constants or dipole moments.
 
BilZ0r said:
Okay, I got into an arguement with someone. I don't know a lot about chemistry, but I'm sure I'm right. He has a PhD is plant-extract pharmacology (including the chemistry) so he should be right.

Anyway, he says, long chain primary alcohols are more polar that short ones, i.e. butanol is more polar than methanol.

I say that is rubbish because more carbons can donate more electrons to the oxygen, reducing the polarity, and of course long chain alcohols don't disolve in water (where do they stop? Pentanol?) Thanks.
Click to expand...

You are right. Miscibility with water stops around 1-butanol I think. Longer chains bend around and present huge hydrophobic sections in addition to blocking the alcohol function from forming hydrogen bonds. If you look up the dipole moments in the CRC (mine is in a box somewhere), you'll undoubtedly see a decrease with chain length. Maybe he was focusing on some obscure element of polarity?
 
Is there a way for chemists to verify the substance they just made is the substance they wanted to make? You know, making sure they didn't make a mistake somewhere along the process. Is it an easy way and is it often used - if there's one?
 
Hanlons_Razor said:
And can someone give me a brief rundown on oxidation numbers and why they turn different colors? My chem class kinda skipped right by this and I thought it was cool...but I had to hand in my chem book, which meant I couldn't work it out over the summer.
Click to expand...

Well chemistry was awhile ago for me but I think I remember this. Oxidation numbers are basically just indicating what configuration of electrons an atom has. Transition metals may have a few different states that are stable, so there's different varieties depending on what the oxidation state is.

As for the different colors, if I remember this has to do with the electrons as well. When electrons release energy by dropping from an outer shell to an inner one, they give off a photon. The energy of the photon has to be equal to the energy lost by the electron (conservation). That value determines the frequency of the photon, and hence its color. Higher energy = more blue, lower energy = more red. The colors produced tend to be very specific to individual elements, and this is how a spectrometer works and how we figure out what elements are in the sun or other stars.
 
Survival0200 said:
Is there a way for chemists to verify the substance they just made is the substance they wanted to make? You know, making sure they didn't make a mistake somewhere along the process. Is it an easy way and is it often used - if there's one?
Click to expand...

There are different types of chromatography used, depending how much money you have.

GC-MS is the best way of determining what substances are contained in a mixture.
 
You can't really use just one technique to absolutely, positively identify a substance. Sure GC-MS is touted as this great thing and is so accurate and is the only thing that will positively identify what you have in a pill, and in the case of known drug determination that's true. It's a pretty cheap, fast and easy method of determining and quantifying known drugs and substances.

But lets say you've created something completely new which has never been characterized before. You shoot it onto a GC-MS and assuming it doesn't decompose at oven temps eventually comes out after a certain period of time giving you a retention time and then onto the Mass Spec, which gives you a mass fragmentation pattern. Both very useful pieces of information, but you're nowhere near actually figuring out what you're compound looks like.

To actually piece together a picture and come up with what you have you need other pieces of data. And luckily there is a vast array of techniques that can be used such as NMR, UV/Vis, IR, Raman, elemental analysis and many more. Individually each of these can tell you a bit about what you have, but definitely can't give you a complete picture.

But even if you have all the data in the world, spat out by the highest precision most ungodly expensive machines in the world, without a competent chemist who can analyze this information and make it fit all together, it's pretty much worthless.
 
Depends on what you mean by verify. To me it means having more than one single test, each independent of each other, say the same thing. In the same way two witnesses collaborate a story.

So how many witnesses do you really need? Maybe the context and a crappy witness is just enough, and most of the time, all you have.
 
Here's a (hopefully) easy one to throw out to the chemists:

What are the best ways to wash extracts from psilocybe mushrooms and dmt-containing plants?
 
Well, "washing" of solid extracts is rarely a useful method of purification, I would suggest to dissolve in a suitable solvent, to filter and to recrystallize.

For details you may search the Rhodium archives at Erowid or look at the Lycaeum forums or the shroomery.org
 
I got a real one this time, its about Molecular Geometry.
How does for example, the Hydrochloride, bond to a chemical like, say, Mescaline.
Im sure Ill learn this next sem. in Chem 2, but I just cant wait and want to know now!
Thanks!
 
The hydrochloride (acid) forms a salt (ionically bonded compound caused when acid meets base) with the slightly basic amine tail. The freebase (unsalted) versions of most phenethylamines are oils, while the salts are crystalline solids (with lower and higher melting points, respectively).
 
Smyth said:
http://www.yerkes.emory.edu/DIV/Howell/PB&B80.pdf

The above paper is littered with the type of expressions listed below.

[F(2,48 )=6.213, p>0.04]

Can anybody explain what these mean or direct me to a resource where I can find out?
Click to expand...

It's the outcome of the 2-way ANOVA to test for a difference in mean between samples classified by 2 factors.

http://www-09.nist.gov/div898/handbook/prc/section4/prc43.htm

http://www.calvin.edu/~rpruim/courses/m243/F03/handouts/anova2.pdf

They used RTI-112 in PET imaging studies of monkeys self-administering cocaine.
 
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