🚀 go-pugleaf

On Feb 26, 2:44 pm, Darwin123 <drosen0...@yahoo.com> wrote:

>      The second law of thermodynamics implies that entropy is an
> indestructible substance.
>     The word heat, as used in science articles, can mean one of four
> mutually exclusive things.
> 1) A quantity of entropy.
> 2) The quantity of energy being carried by a quantity of entropy.
> 3) Entropy density.
> 4) The density of energy carried by entropy.
>        The choice of meaning is context sensitive. However, for most
> situations the difference isn't important. However, sometime is is
> very important and causes confusion.
>       Thus when we define enthalpy as the "heat of reaction," we are
> talking about heat in the sense of #3.
     Correction. The heat of reaction implies #4.
    The use of four different meanings is especially confusing to new
students because all four quantities have different units.
1) Joules/degrees Kelvin
2) Joules
3) Joules/degrees Kelvin/meter^3
4) Joules/meter^3
      The laws of thermodynamics are almost always  quoted in terms of
#1. "Heat" is the quantity of entropy. The questions in introductory
physics problems are almost always asked in terms of #2. "Heat" is a
quantity of entropy. Some students instinctively pick up the
difference, and others do not.
    Aside from paranoia, you are victim of an educational system which
is sometimes too pragmatic. Philosophy is important in science. You
can't go far in science without knowing a little semantics.
      My high school chemistry teacher encouraged class discussions on
how the students did the problem. If one student was confused by the
way a another student did the problem, they discussed it even if the
other student was right. We were encouraged to discuss the language
and philosophy of science.