Chemistry 2100 Carbon Oxidation Numbers Handout
When dealing with carbon compounds, one problem arises with the conventional method for determining
oxidation numbers. It calculates the AVERAGE oxidation number but this does not tell us anything about
the oxidation of individual atoms. To determine where the chemical change has actually occurred, we need
to know which atoms have been oxidized or reduced (ie. LEO or GER). The following allows us to
determine the oxidation number for each carbon within the molecule.
TUTORIAL:
Now let’s deal with a molecule that is not so obvious. Lets start with ethanol. It has two carbons but just by
looking at them, you might guess that they do not have the same level of “oxidation” (one is attached to an
oxygen atom where the other is not). Lets work through this molecule and try some others for practice.
PRACTICE: Classify each of the compounds as to their functional group (ether, aldehyde, etc.) and
determine the oxidation number for each carbon within the following molecules. I have
given the oxidation numbers for you to check your answers.