Experimental Investigations
IN THIS CHAPTERSummary: The free-response portion of the AP exam will contain a question con-
cerning an experiment, and there may also be a few multiple-choice questions on
one or more of these experiments. This chapter reviews the basic experiments that
the AP Exam Committee believes to be important. You should look over all of the
experiments in this chapter and pay particular attention to any experiments you
did not perform. In some cases, you may find, after reading the description, that
you did a similar experiment. Not every AP class does every experiment, but any of
these experiments may appear on the AP exam.
The free-response questions on recent exams have been concerned with the
equipment, measurements, and calculations required. In some cases, sources of
error are considered. To answer the question completely, you will need an under-
standing of the chemical concepts involved.
To discuss an experiment, you must be familiar with the equipment needed.
In the keywords section at the beginning of this chapter is a complete list of
equipment for the experiments (see also Figure 19.1). Make sure you are famil-
iar with each item. You may know an item by a different name, or you may
need to talk to your teacher to get additional information concerning
an item.
In some cases, the exam question will request a list of the equipment needed,
while in other cases you will get a list from which to choose the items you need.
Certain items appear in many experiments. These include the analytical balance,
beakers, support stands, pipets, test tubes, and Erlenmeyer flasks. Burets, gradu-
ated cylinders, clamps, desiccators, drying ovens, pH meters, volumetric flasks,
and thermometers are also commonly used. If you are not sure what equip-
ment to choose, these serve as good guesses. Most of the remaining equipment
appears in three or fewer experiments.
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