What is an example of a Boyle's law practice problem?

1 Answer
Jul 16, 2014

Boyle's Law, a principle that describes the relationship between the pressure and volume of a gas. According to this law, the pressure exerted by a gas held at a constant temperature varies inversely with the volume of the gas. For example, if the volume is halved, the pressure is doubled; and if the volume is doubled, the pressure is halved. The reason for this effect is that a gas is made up of loosely spaced molecules moving at random. If a gas is compressed in a container, these molecules are pushed together; thus, the gas occupies less volume. The molecules, having less space in which to move, hit the walls of the container more frequently and thus exert an increased pressure.

Stated as a formula, Boyle's Law reads:

V1/ V2= P2/ P1 (at constant temperature)

where V1 equals the original volume, V2 equals the new volume, P1 the original pressure, and P2 the new pressure.

An unknown gas has an initial pressure of 150 kPa and a volume of 1 L. If the volume is increased to 1.5 L, what will the pressure be now?
V1 = 1L P1 = 150 kPa
V2= 1.5 L P2 = ?

1L/ 1.5 L = P2 / 150 kPa

P2 = 150 kPa x 1 L / 1.5 L

P2 = 100 kPa.