January 21, 2004
A: FROM MENTOR JOAN LUSK IN RI
You're in the awkward position that many first-year college students find
themselves in - they are in the freshman chemistry course, which assumes a
high-school background, but they don't remember a thing from the chemistry
they had in sophomore year.

What I'd advise you to do is to borrow a copy of the textbook from the
regular course that you skipped, and talk with the teacher of that course
and the teacher of the AP course. The AP teacher will have some expectation
of what the students should know coming into the course, and with luck that
will actually correspond to what the regular-course teacher expected
students to learn! Talking to both will tell you what to focus on and what
parts of the book are not essential.

If I were to guess at what's important, without knowing what your teachers
decided, I would say:
1. the idea that matter is particulate; moles and stoichiometry
2. the idea that you can solve quantitative problems. (How much of A does
it take to react with a gram of B and how much product is produced?)
Knowing how to set up equations from a verbal description of a problem
("word problem"). Much of elementary chemistry boils down to algebra after
the problem is set up properly - in a way, by waiting to start chemistry you
may have learned more math and put yourself in a stronger position. You
should do some of the problems from the more elementary textbook, to see if
you really understand the material and can use it.
3. Electronegativity. What elements react with what other elements.
4. Electronic structure. What the periodic table means. How molecular
structures depend on the electronic structures of the atom that comprise
them.

Beyond these fundamentals, individual teachers may have stressed different
things. How gases behave; acids and bases and other equilibria; the
thermodynamic equations underlying these phenomena; more descriptive
chemistry of the elements... Do talk with the teachers - don't expect to
guess right.