Lab 4 out, please Results? Yield? Errors? Laptops out but not up yet Warm-Up (Oct 9) Lab 4 out, please Results? Yield? Errors? 2) Unit 2 Gases = Ch 5! Laptops out but not up yet

Lab 4: Alum (lab books to me) Hydrate number? Percent yield? 12 is the hydrate number Yields are low due to transfers, crystallization, buchner funnel, etc

UNDER PRESSURE – online sim (5 minutes) What is gas pressure? Try to explain in your notes after looking at the simulation for a while. Answer the questions on the sim! http://www.physics-chemistry-interactive-flash-animation.com/matter_change_state_measurement_mass_volume/pressure_volume_boyle_mariotte_law_ideal_gas_closed_system_MCQ.htm Ping pong balls?

Gas Pressure Intro Pressure = force / area Collisions with the container Temperature is related to speed of particles Units of pressure: 1 atmosphere = 760 torr or mmHg = 14.7 psi = 101.325 kPa

Balloon Time! Explain: Equilibrium! (Remember back to day 1 demo….water got pushed in!=

Boyle’s Law (Pressure and Volume) Demo! P = k 1 V If you have an original gas sample with a volume of 5.0 L and a pressure of 1.2 atm, what is the new volume if the pressure is decreased to 0.75 atm? Vacuum chamber! And marshmallows, 8.0 L

Syringe Time! Where are the molecules? How are they behaving? Calculate the pressure of the compressed syringe assuming today’s pressure is 1.1 atm.

Charles’ Law (Volume and T) Demo I wish! V = b T This is a tough one! If we want to keep Pressure constant, the temperature actually has to go DOWN so that there are the same number of collisions as before.

Temperature Conversion Important!! You MUST convert Celsius to Kelvin! What is the conversion? K = C + 273.15

Avogadro’s Law (V and n) Demo: what happens when more molecules are added? V = a n Blow into the balloon

Apply the laws! If a container can only swell to 7.2 L before it breaks, and a sample of gas is inside at 30.0 C is 2.5L, what temperature (in C) of gas will cause the container to break? 600 Celsius (don’t forget to convert to KELVIN)

Reminders of Laws (5.2) (Boyle’s) When P increases, V (Avogadro’s) When n increases, V (Charles’) When T decreases, V

“STP” Important Info! Standard Temperature and Pressure P = 1.00 atm T = 273 K, or O °C

Ideal Gas Law! (5.3) Let’s put it all together: PV = nRT Independent of the type of gas – volume is equal no matter the molar mass!

Deriving R – Lab 5 next class Let’s look at your AP Equations sheet…

Intro WS Practice (HW) Show all work!

Homework Unit 2 Day 1 No class or lab Wednesday  Happy PSAT  Lab 5 in class Friday! Come prepared! Finish WS Day 1 for Homework by Friday Class It’s long, but I’m cancelling lab so NO COMPLAINTS! Chapter 5 reading: 5.3, 5.5, 10.8