Warm-Up April 9, 2013

1. Warm-UpApril 9, 2013 • Write down the date and objective. • Objective: SWBAT apply the concepts of the Kinetic Molecular Theory by completing the Practice Problems. • Complete the following warm-up: • Why should you not fill your car tires to their maximum pressure capacity during the winter? How can you summarize the relationship between pressure and temperature using this example? • What would happen to the gas pressure in the tire if you reduced the volume of the tire to half its size? How can you summarize the relationship between volume and pressure using this example?

2. Objective & Agenda • Objective: SWBAT apply the concepts of the Kinetic Molecular Theory by completing the Practice Problems. Agenda • Mystery Element • Flashback • Gas Laws • Whiteboard Review • Practice Problems • Exit Slip

3. Mystery Element Clues • It is the ninth most abundant element in Earth’s crust. • In its pure state it is a shiny, white metal that is easy to work and quite ductile, or capable of being drawn into wire. • It is named for the Titans of Greek mythology.

4. Titanium (Ti) • Titanium is a transition element • Titanium has a density approximately 40% that of steel. Despite its light weight, it is unusually strong. • It is an ideal structural material for rockets and jet engines because it does not corrode. 10,000 pounds of titanium and its compounds are used in each engine of a Boeing 747 jet! • Titanium pins are often used in surgery. • The U.S. Navy used titanium (IV) chloride during WWII to make smoke screens when it was necessary to block a potential target from view.

5. Yesterday

6. Kinetic Theory and a Model for Gases Skier • Kinetic energy: the energy an object has because of its motion. • Potential energy: stored energy. • Kinetic theory • Tiny particles in all forms of matter are in constant motion KE and PE song

7. Kinetic Molecular Theory Video • http://www.youtube.com/watch?v=_rsqBNhFG1Y

8. The Kinetic Theory! Gases (Kinetic Theory) • Gases are small spheres that have insignificant volume and are far apart from each other. • Gas particles move rapidly , moving in straight paths (independently of each other) • This is why gases fill their containers • All collisions between gas molecules are perfectly elastic • Meaning the amount of kinetic energy stays constant (no energy is lost).

9. Gas Pressure • Gas pressure: the force exerted by a gas on an object. • Result of simultaneous collisions of billions of rapidly moving gas particles. • Vacuum: empty space with no particles and no pressure. • Atmospheric Pressure: measures amount of collision of air particles with objects • Barometer: measures atmospheric pressure. • Units of Pressure: • Pascal (Pa), standard atmosphere (atm), mm of Hg • 1 atm = 760 mm Hg = 101.3 kPa

10. STP, Average Kinetic Energy, and Temp. • STP: standard temperature and pressure • 1 atm and 0°C • High temperature= higher kinetic energy= faster moving particles • Kelvin temperature • Water freezes at 273K so… • 273K = O°C • Add 273 to go from °C to Kelvin

11. Gases • Gases are compressible, measure of how much the volume of matter decreases under pressure. • Easily compressed because of the space between particles • The amount of gas, volume, and temperature are factors that affect gas pressure.

12. Gas Laws Introduction • http://ed.ted.com/lessons/1207-1-a-bennet-brianh264

13. Gas Laws • Boyle’s Law: relates pressure and volume (P&V) • Charles’ Law: relates temperature and volume (T&V) • Gay-Lussac’s Law: relates pressure and temperature. (P&T)

14. Boyle’s Law • If temperature is constant, as the pressure of a gas increases, the volume decreases. P1V1 = P2V2 • Animation EX: A balloon contains 30.0L of helium gas at 103 kPa. What is the volume of the helium when the balloon rises to an altitude where the pressure is 25.0kPa?

15. Boyle’s Law Guided Practice • Nitrous oxide (N2O) is used as an anesthetic. The pressure on 2.50L of N2O changes from 105 kPa to 40.5 kPa. If the temperature does not change, what will be the new volume? • A gas with a volume of 4.00L at a pressure of 205 kPa is allowed to expand to a volume of 12.0L. What is the pressure in the container if the temperature remains constant?

16. Charles’ Law • As the temperature of an enclosed gas increases, the volume increases, if the pressure is constant. V1 = V2 T1 T2 • Temperature must be in Kelvin!! • Animation • EX: A balloon inflated in a room at 24°C has a volume of 4.00L. The balloon is then heated to 58°C. What is the new volume if the pressure remains constant?

17. Charles’ Law Guided Practice • If a sample of gas occupies 6.80L at 325°C, what will its volume be at 25°C if the pressure does not change? • Exactly 5.00L of air at -50°C is warmed to 100.0°C. What is the new volume if the pressure remains constant?

18. Gay-Lussac’s Law • Assuming constant volume, as the temperature increases, the pressure increases, and vice versa. P1 = P2 T1 T2 EX: A sample of nitrogen gas has a pressure of 6.58kPa at 539K. If the volume does not change, what will be the pressure at 211K?

19. Guided Practice • A sample of nitrogen gas has a pressure of 1.25 atm at 52.4°C. If the volume does not change, what will the temperature be, in Celsius, if the pressure decreases to 0.75 atm?

20. Independent Practice • Complete the Gas Law Practice Problems on a separate sheet of paper. • ONLY COMPLETE PART 1!

21. HW21- Gas Law Practice • Due Thursday

22. Exit SlipApril 9, 2013 1. Divers get “the bends” if they come up too fast because gas in their blood expands, forming bubbles in their blood. If a diver has 0.05 L of gas in his blood under a pressure of 250 atm, then rises instantaneously to a depth where his blood has a pressure of 50.0 atm, what will the volume of gas in his blood be?