Boyle’s LawBoyle’s Law

Pressure versus VolumePressure versus Volume

Boyle’s Law: P and VBoyle’s Law: P and V Discovered by Discovered by Irish chemist, Irish chemist, Robert BoyleRobert Boyle

Used a J-shaped Used a J-shaped tube to tube to experiment with experiment with varying varying pressures and pressures and their effects on their effects on the volume of an the volume of an enclosed gas.enclosed gas.

Pressure versus Pressure versus VolumeVolume

as one as one increasesincreases, the , the

other other decreasesdecreases inversely proportionalinversely proportional pressure is caused by moving pressure is caused by moving molecules hitting container wallsmolecules hitting container walls

If volume is decreased and the # If volume is decreased and the # of molecules stays constant, of molecules stays constant, there will be more molecules there will be more molecules hitting the walls per unithitting the walls per unit

Boyle’s Law: P and VBoyle’s Law: P and V

Boyle’s LawBoyle’s Law states that the states that the volume of a fixed mass of gas volume of a fixed mass of gas varies inversely with varies inversely with pressure at a constant pressure at a constant temperature.temperature.

k = VxPk = VxP k is a constant for a certain k is a constant for a certain sample of gas that depends on sample of gas that depends on the mass of the gas and the the mass of the gas and the temperature.temperature.

What kind of graph is V vs. What kind of graph is V vs. P?P?

Boyle’s LawBoyle’s Law

If we have a set of new If we have a set of new conditions for the same conditions for the same sample of gas, they will sample of gas, they will have the same k so:have the same k so:

2211 VPkVP

2211 VPVP

Example: Boyle’s LawExample: Boyle’s Law

Consider a 1.53-L sample of gaseous Consider a 1.53-L sample of gaseous SOSO22 at a pressure of 5.6 x 10 at a pressure of 5.6 x 1033 Pa. Pa. If the pressure is changed to 1.5 x If the pressure is changed to 1.5 x 101044 Pa at constant temperature, what Pa at constant temperature, what will be the new volume of the gas?will be the new volume of the gas?

L 0.57Pa 101.5

L) (1.53 Pa) 10 (5.6V

4

3

2

2

1122211 P

VPV so VPVP