Ask A Scientist Materials Science Archive

name         Elliot R.
status       student
grade        6-8
location     MI

Question -   I would like to know, how chemicals are engineered. What
I mean is how do scientists get different atoms to combine. For instance,
if I wanted to get a Oxygen atom to bind with a carbon or any other, how
to scientists get them to do so, especially if they are different types
of things, like a solid and a liquid or gas. There must be some way they
do it other than just mixing them. I find this extremely interesting.
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Here are my observations, as an engineer, as opposed
to a scientist.

First, addressing states.  A pencil lead is basically
carbon.  Air, has oxygen.  With the pencil exposed
to air, Is there any combining? No.  So there given
states define a stability.  But, their properties are affected by their
environment.  Raise the temperate and the pencil lead would melt.  The atoms
within the carbon get excited, increasing the potential for
combining with other atoms.  If oxygen is introduced
at its excited state it will combine with the carbon.  Quantities are
critical.  Temperature is but one of the properties that have impact.
Pressure is another.  One reason for the President's plan to go to the moon,
is for industry.  The lack of gravity permits chemicals to be combined, at
far less expense than on earth.  This would be advantageous to drug companies
and other industries.

James Przewoznik
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Elliot,

The whole of Chemistry is a science that tries to understand and organize 
the experiences we have with chemicals. Thus, controlling reactions so 
that they go the way we want them to is a result of this understanding. 
Here is a short summary: Chemists view matter (nature) as being made up of 
atoms. All atoms have structure. Part of the structure of atoms are its 
electrons. It turns out that most of the chemical and physical properties 
of atoms can be attributed to the outermost layer of electrons that an 
atom has (think of the way all our physical interaction is through our 
skin). Knowing the structure of this outermost layer of electrons - which 
differs from atom type to atom type - gives us an idea of how the atom 
will respond or interact in various situations. Thus, controlling a 
reaction really comes from our understanding of atoms.

Greg (Roberto Gregorius)
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The answer to your question is far beyond the scope of  a medium like
NEWTON BBS, because you are asking in effect, "What is organic synthesis?"
and the answer to that question fills library shelves -- hundreds, maybe
thousands of them. In general, a chemist has a "reason" for wanting to
synthesize a particular compound. This motive could range from "because it
looks interesting" to "similar molecules have interesting, possibly
commercial value". S/he then researches what starting compounds are
available, or can be synthesized. Then comes the creative part, "How can I
get from the starting material to the desired end product most efficiently
and/or most cost effective?" The answer to that question is tied up with
the first. The more the motivation is commercial, the more important cost
effectiveness becomes. Over time, particularly the last century, a vast
literature on how to get from compound A to compound B has evolved. The
chemist researches the literature for possible routes, or in the absence of
any known route, s/he may have to invent one. It is here where the
creativity of the chemist comes into play. Conditions of synthesis --
temperature, pressure, catalyst, solvent(s), etc. are arrived at
experimentally, and/or experience about what does/does not work. You are
correct, just dumping "stuff" into a flask, stirring and heating, is not a
very efficient, or safe way to arrive at conditions.
     Most synthetic organic chemists specialize in the synthesis of certain
sub-categories of compounds. If a chemist needs a method, or believe s/he
needs a reaction, s/he may likely communicate with a specialist in that type
of reaction. Most chemists willingly trade their knowledge unless there are
patent or trade secrets involved. Then starts the hard, labor intensive,
work. Making "educated guesses" and trying them  out. Usually, this may
involve developing a new body of synthetic knowledge, which the chemist will
share through publication in the open literature. Sometimes this process
leads the chemist to a "fork in the road" and s/he will change the original
objective because a new topic/method is uncovered during the discovery
process.
     All of this is quite challenging and is how new syntheses are
discovered.
Vince Calder
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