Re: [Phys-l] macromolecules

[Stefan Jeglinski <jeglin@4pi.com>]

> Basic notions such as the law of definite proportions and what it 
> means to balance a chemical reaction are taught in ways that are 
> contradicted by the example of macromolecules.

Can you expand with a worthy example?

For instance, I would assume that your reference to the law of 
definite proportions could refer to the reality of non-stoichiometric 
compounds. Why would this be any different from a real crystal, which 
exhibits defects? Our band discussion implicitly idealized crystals, 
for example, but no one I know of expects real crystals to match the 
theory, in many cases. I would expect likewise that chemists, while 
teaching the so-called law of definite proportions, acknowledge the 
reality of non-stoichiometric compounds. I would view this as an 
implicit, if not explicit, admission of the existence of 
macromolecules, and on another, non-introductory level, would be 
considered in detail.

> Yet macromolecules are practically taboo in introductory chemistry.

Perhaps in the same sense that real crystals with point defects (etc) 
are practically taboo in introductory solid state physics? In 
learning about band structure, I always understood (ie, "was taught") 
the idealizations behind the free-electron or tight-binding 
approximations, for example. To be able to learn certain concepts, we 
never let the facts get in the way :-)

To cite another example, air drag is typically "taboo" in 
introductory kinematics, in my experience, but is never denied as 
real. And when going beyond the introductory, it is both acknowledged 
*and* included. Perhaps I misunderstand your use of "introductory."


Stefan Jeglinski