Open-Notes QUIZ TODAY Over: Pressure, Fluids, Gas Laws.

Open-Notes QUIZ TODAY

Over: Pressure, Fluids, Gas Laws

Gas Laws

Bellwork – When gas in a hot-air balloon is heated, does it become more dense or less dense

( why does the balloon rise? )

Gas Laws

Bellwork – When gas in a hot-air balloon is heated, does it become more dense or less dense

( why does the balloon rise? )The gas is less dense / more spread out

Particles are further apart

Gas Laws

• How did we define a LAW?

Gas Laws

• How did we define a LAW?

• PREDICTS some action or behavior

• Gas Laws predict gas behavior in specific conditions

• CONDITIONS are Pressure, Temperature, Volume

Temperature

• When we deal with temperature in these gas laws, absolute temperature is used

– Kelvin scale

– Through examples, you will see why we have the Kelvin scale

Bellwork – 02/05/15

• With constant temperature, do you think pressure and volume are directly or inversely proportional?

• inversely

– We will use a simulation

Boyle’s Law• Product of pressure and volume is constant– Temperature is held constant

• Pressure and Volume are INVERSELY Proportional

• P1V1 = P2V2 = CONSTANT

• “1” indicates initial conditions or a “before”

• “2” indicates final conditions or an “after”

Gay-Lussac’s Law

Charles’s Law

Go back to Labtops –TAKE NOTES

• Again at the PhET site, search for “Gas Properties” simulation

• RUN simulation

• Add gas ( choose light species ) – set value to 1

• See that this number tells you # of particles

• Increase gas value to 150 (USE PUMP , then adjust)

Example of Boyle’s Law

• If a gas has a volume of 325 mL at a pressure of 478 mmHg, what will the pressure be at a volume of 416 mL?

• P1V1 = P2V2 = CONSTANT

Example of Boyle’s Law

•P1V1 = P2V2 = CONSTANT

•( 478 ) * ( 325 ) = 155350 ( our constant )

•155350 = P2V2 = P2 * ( 416 )

•P2 = 155350 / 416 = 373 mmHg

Using Boyle’s Law

• From this example, how are pressure and volume related?

• As Pressure increased, volume decreased– The opposite can happen ( vol increase, pressure

decrease )

• This is what meant by INVERSELY proportional