Friday April 24 Take out kinetic molecular theory notes to be stamped Objective: Use the ideal gas law to solve problems. Checkpoint: – You car tires have a 25 L of air at 25⁰C and 202 kPa. You drive your car and the tires heat up to 42⁰C with a pressure of 198 kPa. What is the new volume of your tires? Homework: Absolute zero lab (due Monday) Ideal Gas Law 6 problems (due Monday) Gases Exam (Wed/Thurs)

Combined Gas Law after Temperature must be in Kelvin! You car tires have a 25 L of air at 25⁰C and 202 kPa. You drive your car and the tires heat up to 42⁰C with a pressure of 198 kPa. What is the new volume of your tires? before P 1 = V 1 = T 1 = P2 =P2 = V2 =V2 = T2 =T2 = 25 L 298 K 202 kPa 198 kPa 315 K

Combined Gas Law after before (298 K) = V 2 = L P 1 = V 1 = T 1 = P2 =P2 = V2 =V2 = T2 =T2 = 25 L 298 K 202 kPa 315 K 198 kPa Temperature must be in Kelvin! (198 kPa) (V2)(V2) (315 K) (202 kPa)(25 L) (298 K) (198 kPa) (298 K) (198 kPa)

Absolute Zero Project What is the coldest possible temperature? Prove it! Record temperature and pressure of a gas in 5 different conditions. – Room temp – Boiling water – Ice bath – Dry ice – Isopropyl alcohol

Dry ice Ice water Isopropyl alcohol Room temperature Boiling water Temperature ( ⁰ C) Pressure (torr) Trial 1 Trial 2 Trial 3 Average pressure (torr)

Make your graph X axis (temperature in K) Y axis (pressure in torr)

How much pizza should you order for a party of 6 people?

Ideal Gas Law Temperature must be in Kelvin! Pressure must be in atm! Volume must be in L. R =

(5.6 atm)(12 L) = (4 mol)(0.0821)(T) (4 mol)(0.0821) T = 205 K PV n T

(1.03 atm)(31 L) = (n)(0.0821)(360) (0.0821)(360) n = 1.08 mol PVTn 360 K