MHS AP Chemistry
Determination of Fat Content

In this lab we will determine the mass percent of fat in a specific food product (TBA in class).  There will be only the barest outline procedure provided; details are up to the students.  The class will turn in one paper to present their results, and share a grade.

A Note About The Solvent
The recommended solvent is cyclohexane, which is volatile, toxic, flammable, and smelly.  We will most likely use an alternative solvent in the form of paint stripper, which is not quite as volatile, toxic, flammable, or smelly.  There will be no open flames allowed, and as often as possible the solvent fumes should be contained (in the hood, or a vent hose, or some other method).


  1. Decide ahead of time on what data you will need for your calculations.
  2. Get a sample of the food, smash it to bits, and dissolve the fat part of it in our solvent of choice.
  3. Separate the solid bits of food from the fat/solvent solution.  You may decant, filter, centrifuge, or use some other method.
  4. Separate the fat from the solvent.  You may use low-temperature crystallization, distillation, low-pressure distillation, evaporation, or some other method.
  5. Dispose of your waste properly and clean up your lab station.
  6. Calculate the mass percent of fat present in your sample, and write a paper together to present your results.  Make sure everybody agrees the paper is good before it is passed in.
What Should The Paper Include?

[MHS AP Chem page]