Congratulations, you have made it through two semesters of general chemistry, next stop organic chemistry
You are worried, you have heard that organic chemistry is really hard
and you are wondering what you really need to know from general
chemistry to make things easier. The good news for some is most of the math is not required in o-chem.
There are many concepts that carry forward from general chemistry to
organic chemistry, unfortunately most of these concepts were introduced
in the first semester of general chemistry and many students have
forgotten them by the time they take O-chem. Since very little time will
be spent on these topics I feel it is important that all students
refresh themselves on them before entering the course. This will help
you understand what your Professor is talking about when he/she is
introducing more difficult topics.
These are the areas I recommend you review:
1. Lewis structures. These are the diagrams that show the bonding
between the atoms in a molecule. They also show all lone pairs on the
molecules. In addition make sure you understand what a positive and
negative charge means on a molecule. This is the backbone of learning
how to arrow push and draw organic reaction mechanisms. Here are some
examples to try. Carbon dioxide CO2, diazomethane H3CN2, methyl
isocyante H3CNCO, acetamide H3CCONH2, oxalic acid (CO2H)2 .
2. Resonance forms. Be able to draw all resonance forms of a Lewis structure. Try drawing resonances on the above examples.
3. Hybridization. Understand how atomic orbitals are mixed to form
new orbitals suitable for bonding. Be able to label each atom as being
SP3, SP2 or SP1 hybridized. Try the above examples.
4. Understand the different intermolecular forces. (Dipole-dipole,
London dispersion forces, hydrogen bonds, ion dipole, induced dipole
forces). Be able to explain why they have effects on physical properties
of molecules.
5. Stoichiometry. You will not need to know a lot of math for O-Chem
but you will need to work out things like percentage yields and
quantities of materials needed in your lab course.
6. Acid-base chemistry. Understand what makes something
acidic/basic. Organic acids are all weak acids, recall that means they
are not fully dissociated and are in equilibrium with its conjugate
base. The lower the pKa the more acidic something is. Understand what
factors affect the stability of a conjugate base and hence increases the
acidity of the acid. You will not be expected to repeat the
calculations from general chemistry. The reaction between a Lewis acid
(accepts electrons) and a Lewis base (donates electrons) is probably the
most important concept in organic chemistry. This is the back bone of
reaction mechanisms.
If you understand everything above this will be a great starting point for the new materials in organic chemistry. Good luck.
