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 P 1 V 1 = P 2 V 2 = 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? P 1 V 1 = P 2 V 2 = CONSTANT

Example of Boyle’s Law P 1 V 1 = P 2 V 2 = CONSTANT ( 478 ) * ( 325 ) = ( our constant ) = P 2 V 2 = P 2 * ( 416 ) P 2 = / 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