1 / 26

Chapter 12 Section 2

Chapter 12 Section 2. The Gas Laws. Measurable Properties of Gases. Barometer. Manometer. Pressure-Volume Data (Boyle’s Law). Bolye’s Law (Pressure-Volume Relationship). Boyle's Law Animation. Boyle’s Law Equations. P ∙V = k; k is a constant P 1 ∙V 1 = P 2 ∙V 2

saber
Télécharger la présentation

Chapter 12 Section 2

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 12 Section 2 The Gas Laws

  2. Measurable Properties of Gases

  3. Barometer

  4. Manometer

  5. Pressure-Volume Data(Boyle’s Law)

  6. Bolye’s Law(Pressure-Volume Relationship) Boyle's Law Animation

  7. Boyle’s Law Equations • P∙V = k; k is a constant • P1∙V1 = P2∙V2 • The volume is inversely proportional to the pressure • The volume increases (decreases) as the pressure decreases (increases) • The temperature and amount of gas must remain unchanged for this law to work

  8. Pressure vs. Volume

  9. Example A given sample of gas occupies 523 mL at 1.00 atm. The pressure is increased to 1.97 atm, while the temperature remains the same. What is the new volume of the gas? <Solution> P1∙V1 = P2∙V2 P1 = 1.00 atm; V1 = 523 mL P2 = 1.97 atm; V2 = ? (1.00 atm)∙523 mL = (1.97 atm)∙V2

  10. Practices on Boyle’s Law(Do on a separate paper) • A flask containing 155 cm3 of hydrogen gas was collected under a pressure of 22.5 kPa. What pressure would have been required for the volume of the gas to have been 90.0 cm3? • A sample of oxygen gas has a volume of 150. mL when its pressure is 0.947 atm. What will the volume of the gas be at a pressure of 0.987 atm if the temperature remains the constant? • A gas has a presssure of 1.26 atm and occupies a volume of 7.40 L. If the gas is compressed to a volume 2.93 L, what will its pressure be, assuming constant temperature?

  11. 4 Practice Problems Pg 425 4) A sample of oxygen gas has a volume of 150.0 mL at a pressure of 0.947 atm. What will the volume of the gas be at a pressure of 1.000 atm if the temperature remains constant? 5) A sample of gas in a syringe has a volume of 9.66 mL at a pressure of 64.6 kPa. The plunger is depressed until the pressure is 94.6 kPa. What is the new volume, assuming constant temperature? 6) An air mass of volume 6.5×105 L starts at sea level, where the pressure is 775 mmHg. It rises up a mountain where the pressure is 622 mmHg. Assuming no change in temperature, what is the volume of the air mass? 7) A balloon has a volume fo 456 mL at a pressure of 1.0 atm. It is taken under water in a submarine to a depth where the air pressure in the submarine is 3.3 atm. What is the volume of the balloon? Assume constant temperature.

  12. Charles’s Law(Temperature – Volume Relationship)

  13. Charles’s Law Equations 1) 2) 3) The volume and temperature are directly proportional 4) The volume of gas increases (decreases) as the temperature increases (decreases) 5) The temperature MUST be in kelvin 6) Must keep the pressure and the amount of gas unchanged for this law to work

  14. Volume-Temperature Problems A balloon is inflated to 665 mL volume at 27°C. It is immersed in a dry-ice bath. What, at −78.5°C, is its volume, assuming the pressure remains constant?

  15. Practices on Charles’s Law(Do on a separate paper) • A sample of neon gas occupies a volume of 752 mL at 25 ºC. What volume will the gas occupy at 50 ºC if the pressure remains constant? • A helium-filled balloon has a volume of 2.75 L at 20 ºC. The volume of the balloon decreases to 2.46 L after it is placed outside on a cold day. What is the outside temperature? • A gas at 65 ºC occupies 4.22 L. At what Celsius temperature will the volume be 3.87 L, assuming the same pressure?

  16. 4 Practice Problems on Pg 428 4) Helium gas in a balloon occupies 2.5 L at 300.0 K. The balloon is dipped into liquid nitrogen that is at a temperature of 80.0 K. What will the volume of the helium in the balloon at the lower temperature be? 5) A sample of neon gas has a volume of 752 mL at 25.0 ºC. What will the volume at 50.0 ºC be if pressure is constant? 6) A helium-filled balloon has a volume of 2.75 L at 20.0 ºC. The volume of the balloon changes to 2.46 L when placed outside on a cold day. What is the temperature outside in degrees Celsius? 7) When 1.50×103 L of air at 5.00 ºC is injected into a household furnace, it comes out at 30.0 ºC. Assuming the pressure is constant, what is the volume of the heated air?

  17. Gay-Lussac’s Law(Temperature-Pressure Relationship) • As the temperature increases (decreases), the pressure increases (decreases) • Temperature and pressure are directly proportional: • or • Temperature MUST be in kelvins • Works only if the volume and the amount of gas are kept constant

  18. Gay-Lussac’s Law(Temperature – Pressure Relationship)

  19. Example • An aerosol can containing gas at 101 kPa and 22 ºC is heated to 55ºC. Calculate the pressure in the heated can. • <Solution> P1=101 kPa T1 = 22 ºC = 295 K P2= ? T2 = 55 ºC = 328 K

  20. Practices: Pg 431 • At 122 °C the pressure of a sample of nitrogen is 1.07 atm. What will the pressure be at 205 °C, assuming constant volume? • The same sample of nitrogen as in #1 starts at 122°C and 1.07 atm. After cooling, the pressure is measured to be 0.880 atm. What is the new temperature? • A sample of helium gas is at 122 kPa and 22 °C. Assuming constant volume, what will the temperature be when the pressure is 203 kPa? • The air in a steel-belted tire is at a gauge pressure of 29.8 psi (pounds per squared inch) at a temperature of 20 °C. After the tire is driven fast on a hot road, the temperature in the tire is 48 °C. What is the tire’s new gauge pressure?

  21. Combined Gas Law(Volume, Temperature & Pressure) • Combine Boyle’s law and Charles’s law: P1∙V1 = P2∙V2 • For this law to work, the amount of gas must remain unchanged • With this law, 2 variables out of 3 can change

  22. Example 520 mL of hydrogen gas at 750 mmHg and 25 °C is placed in a 1000. mL container and heated to 50 °C. What is the pressure of the gas in the container? <Solution>

  23. Avogadro’s Law(Volume-Molar Relationship) • As the number of moles of gas increases (decreases), the volume of gas increases (decreases) • The volume (V) of gas is directly proportional to the number of moles (n) of gas • or • The type of gas doesn’t affect the volume; only the moles of gas matter (Ex) Having 1 mol of hydrogen gas and 2 mol of carbon dioxide gas gives the same volume as 3 mol of methane gas (Can you think of why?) • For this law to work, pressure and temperature must remain unchanged • 1 mole of any gas takes up 22.4 L volume at STP

More Related