Open-Notes QUIZ TODAY Over: Pressure, Fluids, Gas Laws.
Post on 27-Dec-2015
217 Views
Preview:
Transcript
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?
• 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”
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
top related