Sciencemadness Discussion Board

are amateur chem reactions restricted to ion interactions?

quantumchromodynamics - 16-1-2014 at 10:04

At this time I feel like I have a legitimate comprehension on maybe the first two entry college chemistry courses. Maybe not. :(

My observation and concern is this. It appears I can make reactions do things with poly-atomic and regular ions, like precipitate copper from aluminum using copper sulfate and sodium chloride, or do single displacements, or double displacements, make my own sodium acetate from bicarbonate and acetic acid, and that sort of thing. But what I can't do is get inside the covalent bonds to do anything.

For example, why can't I get phosphorous from phosphate ions, like with tri sodium phosphate, or with phosphoric acid?

I am only able to vaguely grasp why a reaction chooses to go one way or the other, ??when the ionization energy is less than the difference in the electronegativities??, but I don't understand how to apply that statement. Why don't reactions just constantly churn back and forth. Entropy must have something to do with it.

I apologize for not being able to state my question or confusion more clearly. This is my problem. I don't know how to proceed. I don't know what keywords to search for.

Are my thoughts generally correct? What am I missing?

Could anyone add a bit of momentum to this located quantum particle?

DraconicAcid - 16-1-2014 at 10:21

I'd suggest getting a book on organic chemistry, and reading that.

WGTR - 16-1-2014 at 13:32

Honestly, isolating phosphorous is hard for everybody, not just you. Maybe that's not a good example. But from a practical
perspective, precipitating copper from CuSO4, or re-crystallizing KNO3, is easy because it can be done in a beaker by anyone
in their garage, and characterizing the results of the reaction doesn't require any special equipment (your eyeballs).

When oxidizing alcohol to form acetaldehyde, for example, one needs more equipment and expertise; not only to perform the
reaction effectively, but to isolate and identify the various products formed. If one cannot do this analysis, then everything
else is of limited utility. Even making acetaldehyde is not really that hard, but it's just an example for how chemistry gets
more tedious and complicated when you branch away from simple displacement reactions in aqueous solutions.

Having been there myself, I've learned that proper analytical techniques promote learning and troubleshooting with a
particular reaction. Otherwise, I'm just flying blind into a cave of frustration.

MrHomeScientist - 16-1-2014 at 14:01

Regarding why reactions tend to go one way only, or are hard to force in a particular direction, look up "Gibbs Free Energy," or ΔG. This quantity tells you whether a process is spontaneous at standard conditions, and is defined as:
ΔG = ΔH - TΔS
where H = enthalpy, T = temperature, and S = entropy.

H can be calculated from the difference in the standard heats of formation of the reactants and products in a particular reaction (these can be looked up). S is a measure of disorder in the system, so going from solids to gases would be an increase in entropy, for example.
If ΔG is negative, the reaction is spontaneous and (should) proceed. If it is positive, it is nonspontaneous and requires some input to get started. Making elemental phosphorus is very difficult because the reactions that produce it are very unfavorable under standard conditions.

Been a while since I've done this myself, honestly, but this should hopefully get you started.


Edit: Home chemistry is by no means limited to ionic bonds, either. Check out this video by a member here, hkparker: http://www.youtube.com/watch?v=CLnmGJXolpc
In it, he synthesizes iodine monochloride, a covalent interhalogen compound.

[Edited on 1-16-2014 by MrHomeScientist]

vmelkon - 16-1-2014 at 16:23

Personally, what I did was buy used university books. I bought a couple on inorg chem, 1 on org chem, 1 on genetics (but haven't read it), 1 on origin of species (Yes, the Charles Darwin book).

Then start reading chapter by chapter. Knowing concepts and theories is very important. Then you can surf the web, come to these forums, repeat experiments others have done.

And if you don't have money to spend on this hobby, then forget about it.

MrHomeScientist explains an important concept : why reactions go in one direction.

quantumchromodynamics - 16-1-2014 at 20:56

vmelkon: I am serious about this interest, as many chemicals and as much glassware as I have collected this past year. At least half my lab space is now covered with chemicals and chemistry related equipment.

I have the book "organic chemistry" by David Klein, Johns Hopkins University, 2012 edition. A thumbs up or a thumbs down? What good books do you use? What bad books are best avoided?

mrhomescientist: thanks for "gibbs free energy" and "delta enthalpy" as a place to look.

Still, academic books are hard because they feel so unplugged. I made it through my inorganic book supplementing with study guides and information presented on this site and others, i.e. chemistry.com, wooleans site, etc. Most of the time an experiment drove study.

Are there some standard or simply interesting sets of organic experiments to recommend?

DraconicAcid - 16-1-2014 at 21:22

Go to a used bookstore, and see if they have anything really old. Older chemistry books tend to be more interesting, and more down-to-earth, in my opinion.

analytic chemistry book

quantumchromodynamics - 17-1-2014 at 02:02

Wow. I found a really old organic chemistry book and a really old analytic chemistry book for $12. PERFECT.

(spin acquired, location wavy)

ScienceSquirrel - 17-1-2014 at 16:43

If you start from aspirin tablets, you can extract acetylsalicylic acid and crystallise it.
After that you can hydrolyse it and isolate and crystallise salicylic acid.
You can characterise both by melting point.
They are easy, if pure they will give sharp literature melting points.
Reaction of the salicylic acid with methanol will give methyl salicylate.
You can also make copper aspirinate, a brilliant blue complex as well.
Nitration to picric acid if you have the reagents.
If you start from paracetamol you can isolate the pure crystalline compound from the tablets and check the melting point.
Acid hydrolysis and crystallisation will give you the 4-hydroxybenzeneaniline hydrochloride.
Reaction with sodium nitrite in cold acid solution will give you the diazonium salt.
This can be coupled with a solution of sodium salicylate to give an azo dye.
You can start from two over the counter pain killers and sweep through a lot of key chemistry of the late 19th and early 20th century. On the way you will do extractions, crystallisations, lots of reactions, make an ester used in medicine, an explosive and a dye, and develop your technique!

quantumchromodynamics - 17-1-2014 at 17:40

Science Squirrel: Thank you my friend!

Just testing

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