Chapter 3 Sec. 2

The Gas Laws

Force distributed over an area (Newton / meter 2)

Units: N/m2 or Pascal (Pa)

More collisions and greater speed of gas molecules increases pressure

Pressure

Factors that Affect Gas Pressure

TemperatureIncrease of temp Increase of K.E.Increase K.E. increases the pressure

VolumeReducing the volume of a container increases

the pressure

Factors that Affect Gas Pressure

Number of ParticlesIncrease number of Particles Increase PressureWhy do you put more air in your tires in the winter?

Boyle’s LawBoyle’s Law

The volume of a fixed amount of gas varies inversely with pressure of the gas.

P1V1 = P2V2

Boyle’s Law

Pressure Volume

Charles’s LawCharles’s Law

The volume of a gas varies directly with the temperature of the gas.

V1T2 = V2T1

Charles’s Law

Temp Volume

Combined Gas Law

Describe that of Charles's and Boyle’s LawP1V1= P2V2

T1 T2

Solve

A cylinder contains air at pressure of 100 kPa has a volume of 0.75 L. The pressure is increased to 300 kPa. Temp does not change, Find the new volume of air.

P1 = 100 kPa P2 = 300 kPa V1 = 0.75 L

V2 = ?

P1V1 = P2V2 (100 kPa x 0.75 L) = (300 kPa x V2)

0.25 L