Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-l] Learning barriers: was Physics first



Ludwik!

If I understand correctly you are welcome to edit the article, I'm too
lazy to do such -- and I've had the desire to do so more than once.

In answer to your question, I think it's for historical reasons --
originally oxidation was w/ O, then it was generalized. Another example
of historical is the Ben Franklin error, but not necessarily in the case
of electrolytes. The long ago chair of Physical Sciences (small school
then) at UCSBC (College, not U. then) told our class about the last time
the error could have been corrected was at a stds. mtng. of the AIP
wherein the proponent of redirecting current didn't stand up to propose
the change. So the wrong movement of current is locked in, unless we get
another Napoleon.

bc, who regrets the chair's heroic death (He went back in to rescue more
people from a burning plane.) for a selfish reason. (He was my mentor.)

p.s. I think reduction comes (came) from reducing an ore (by for
example, carbon). In that case it is reduced in molecular mass by
substituting electrons only for oxygen's. It has a historical logic.
Perhaps this is why history should be taught in Science classes, since
the lingo evidently is "locked in".
p.p.s I've now read the article and think my mnemonic is much better
than the article's; it does allude to it and the conservation of charge..

Ludwik Kowalski wrote:

What takes away pleasure from learning? One of the factors is confusing
terminology, giving new meanings to words which already refer to
something in common use. This has been discussed in some of our
debates. Below is an illustration, pasted from Wikipedia; the law of
conservation of charge is not even mentioned.

If "oxidation" is loss of electrons then why don't they call it loss of
electrons. And if "reduction" is gain of electrons then why don't they
call it gain of electrons. By the way, reduction (for example in
weight) is usually accomplished by loosing something, not by gaining
something.

Ludwik Kowalski
Let the perfect not be the enemy of the good.

Oxidation and Reduction
The elements involved in an electrochemical reaction are characterized
by the number of electrons each has. The oxidation state of an ion is
the number of electrons it has accepted or donated compared to its
neutral state (which is defined as having an oxidation state of 0). If
an atom or ion donates an electron in a reaction its oxidation state is
increased, if an element accepts an electron its oxidation state is
decreased.
For example when sodium reacts with chlorine, sodium donates one
electron and gains an oxidation state of +1. Chlorine accepts the
electron and gains an oxidation state of −1. The sign of the oxidation
state (positive/negative) actually corresponds to the value of each
ion's electronic charge. The attraction of the differently charged
sodium and chlorine ions is the reason they then form an ionic bond.
The loss of electrons of a substance is called oxidation, and the gain
of electrons is reduction. This can be easily remembered through the
use of mnemonic devices. Two of the most popular are "OIL RIG"
(Oxidation Is Loss, Reduction Is Gain) and "LEO" the lion says "GER"
(Lose Electrons: Oxidization, Gain Electrons: Reduction).
The substance which loses electrons is also known as the reducing
agent, or reductant, and the substance which accepts the electrons is
called the oxidizing agent, or oxidant. The oxidizing agent is always
being reduced in a reaction; the reducing agent is always being
oxidized.
The gain of oxygen, loss of hydrogen and increase in oxidation number
is also considered to be oxidation, while the inverse is true for
reduction.
A reaction in which both oxidation and reduction is occurring is called
a redox reaction. These are very common; as one substance loses
electrons the other substance accepts them.
Oxidation requires an oxidant. Oxygen is an oxidant, but not the only
one. Despite the name, an oxidation reaction does not necessarily need
to involve oxygen. In fact, even fire can be fed by an oxidant other
than oxygen: fluorine fires are often unquenchable, as fluorine is an
even stronger oxidant (it has a higher electronegativity) than oxygen.


_______________________________________________
Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l