Boyle's Law

One of the best know characteristics of a gas is its *compressibility* ...its
ability to be forced into a smaller volume by the application of pressure. The first
quantitative study of the compressibility of gases was carried out by Robert Boyle in
1661. He poured mercury into the end of a J-shaped tube, and noted
that the volume of the enclosed gas decreased. Each addition of mercury increased the
pressure on the gas, and decreased its volume. From these experiments, he formulated the
law now known by his name. According to **Boyle's law, ***the volume of a sample of
gas at a given temperature varies inversely with the applied pressure. *That is, V is
proportional to 1/P. Thus if the pressure is doubled, the volume is halved. Boyle's law
can also be stated in the following form: *Pressure times volume is constant for a given
amount of gas at constant temperature: *To put this in mathematical form PV = constant
(for a given amount of gas at a fixed temperature). Since PV = k, we can write P_{i}V_{i}
= P_{f}V_{f}, where the subscript *i* denotes initial pressure and
volume and *f* indicates final pressure and volume. This is the most useful form of
Boyle's law for problem solving.