Unit 14: Gas Laws Pressure 3 Gas Laws Combined Gas Law (calculations) Print 1-3, 5, 7, 9, 11-16

A. Pressure What is Pressure? Which shoes create the most pressure? Like density Which shoes create the most pressure?

Atmospheric Pressure: weight of air per unit area Gravity Atmospheric Pressure: weight of air per unit area

You can’t drink through the straw unless the atmosphere pushes the liquid. WHY no flow?

A. Pressure Measured with a barometer. At sea level: 1 atm 760 mmHg 760 torr 101.325 kPa 14.7 psi Same pressure as a large truck in one inch

A. Pressure What is 475 mmHg expressed in atm? 1 atm = 760 mmHg = 760 torr = 101.3 kpa What is 475 mmHg expressed in atm? What is 103 kPa expressed in atm? 1 atm = 760 mmHg 475 mmHg x 0.625 atm 103 kPa x 1 atm = 101.3 kPa 1.02 atm

A. Pressure What is 720 mmHg expressed in kPa? 1 atm = 760 mmHg = 760 torr = 101.3 kpa What is 720 mmHg expressed in kPa? What is 2.30 atm expressed in torr? 101.3 kPa = 760 mmHg 720 mmHg x 96.0 kPa 2.30 atm x 760 torr = 1 atm 1748 torr

A. Pressure What causes Pressure? collisions of particles with walls of container. # of Particles Volume Temp

Increasing these causes… A. Pressure effect on Pressure Increasing these causes… # of Particles …..…. Volume ..…………… Temp .……………….

Quick Quiz. 1) If 1 atm = 760 mmHg, then how many atm is 747 mmHg? A) 567,720 atm B) 1.02 atm C) 0.982 atm D) atm’s fo’ money yo’, not emm’H’gees 747 mmHg x 1 atm = 760 mmHg 10

Quick Quiz. 2) Gas pressure is affected by A) temp, volume, and molar mass. B) temp and # of particles. C) volume and size of container. D) temp, volume, and # of particles. 11

B. Boyle’s Law (Pressure & Volume) P ↑ as V ↓ As the volume of the air trapped in the pump is reduced, its pressure goes up, and air is forced into the tire.

B. Boyle’s Law (P & V)

C. Charles’ Law (Volume & Temp) V ↑ as T ↑ Temps must be in Kelvin! A balloon shrinks when submerged in cold water

C. Charles’ Law (V & T)

D. Gay-Lussac’s Law (Pressure & Temp) P ↑ as T ↑ Temps must be in Kelvin!

D. Gay-Lussac’s Law (P & T) In a pressure cooker, food cooks faster than in an ordinary pot with a lid. pressure cooker

E. Combined Gas Law (P, V, & T) P, V, & T calculations

E. Combined Gas Law (P, V, & T) P, V, & T calculations Boyle’s Law

E. Combined Gas Law (P, V, & T) P, V, & T calculations Charles’ Law

E. Combined Gas Law (P, V, & T) P, V, & T calculations Gay-Lussac’s Law We add in Avogadro’s Law (n) tomorrow

E. Combined Gas Law (P, V, & T) P, V, & T calculations A 5.00 L balloon is filled with gas at 0.855 atm and 25oC. What is the balloon’s volume at STP? STP = Standard Temp. & Pressure 0oC (273 K) & 1 atm

E. Combined Gas Law (P, V, & T) P, V, & T calculations A 5.00 L balloon is filled with gas at 0.855 atm and 25oC. What is the balloon’s volume at STP? (0.855 atm)(5.00 L) (298 K) (1 atm) V2 (273 K) = (0.855 atm)(5.00 L)(273 K) (298 K)(1 atm) = V2 = 3.92 L

Quick Quiz! 1) A balloon is slightly smaller when moved from a mountaintop to the seashore. The gas law that explains this change is… A) Gay-Lussac’s Law. B) Boyle’s Law. C) Charles’ Law. D) Brock's Law . You’re on the clock. Get to work! Do or do not. There is no try. 24

Quick Quiz. 2) If the temperature of a gas in a flexible container were doubled, the volume of the gas would be A) halved. B) doubled. C) the same. D) stupid anyway. 25

Quick Quiz. 3) If the pressure of a gas in a flexible container were doubled, the volume of the gas would be A) halved. B) doubled. C) the same. D) when am I gonna use this stuff anyway. 26