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Chapter 11 Review The Behavior of Gases The ____________________ is equivalent to 1000 pascals. • kilopascal The term ___________________ refers to temperature of 0ºC and a pressure of 1.00 atm. • standard temperature and pressure The relationship between the pressure and volume of a sample of gas at constant temperature is a(n) ____________________ proportion • inverse The pressure needed to support a 760 mm column of mercury is known as one _________________________. • standard temperature and pressure Why does pumping additional air into a tire cause the pressure inside the tire to increase? • A tire is tough and does not expand easily. The additional air causes the rate of collision of molecules with the inner wall of the tire to increase, thus increasing the pressure inside the tire A tire gauge at a gas station indicates a pressure of 32 psi in your tires. What is the pressure in your tires in kPa? • 320kPa = 101.3 x 32 If the gas pressure in an aerosol can is 166 kPa at 17ºC, what is the pressure inside the can if it is heated to 195ºC? • 17 C = 290 K, 195 C = 468 K • Use combined gas law, volume is constant • 166kPa /290 = P/468 • P = 268 kPa A cylinder of compressed gas has a volume of 3.85 L and a pressure of 463 kPa. What volume would the gas occupy if it were allowed to escape into a balloon at a pressure of 110 kPa? Assume constant temperature. • 3.85 x 463 = V x 110 • V = 16.2 L A gas occupies a volume of 30 mL at 700 mm Hg. What will the volume of this gas be at 800 mm Hg? • 30 x 700 = 800V • V = 26.25 11. At 532 mm Hg and 85ºC, the volume of a sample of nitrogen gas is 26.3 L. What is the volume at STP? • STP = 273 K and 1 atm • Convert C to K, convert mmHg to atm • Use combined gas law • .7 x 26.3/358 = 1 x V/273 • V = 14 A weather balloon on Earth's surface looks as if it is almost empty and barely inflated. As it floats upward, it becomes increasingly larger and at some point becomes fully inflated. How do you explain this process? • As the balloon ascends, the atmospheric pressure on the balloon decreases. Then the gas in the balloon expands as the pressure inside the balloon remains equal to the atmospheric pressure. At 20ºC, a sample of nitrogen gas occupies 25.0 L. What volume will the nitrogen occupy at 225ºC? • 25/293 = V/498 • V = 42.5L Carbon dioxide gas is stored in a steel container with a volume of 12.5 L under a pressure of 50.0 atm. What volume will the gas occupy when it is released from the container into a pressure of 1.00 atm? • 12.5 x 50 = V x 1 • V = 625 L The pressure in a bicycle tire is 1.34 atm at 33.0 °C. At what temperature in C will the pressure inside the tire be 1.60 atm? Assume that the volume will remain constant. • Convert C to K to calculate then back to C for the answer • 1.34/306 = 1.6/T = 365.4 K - 273 = 92.4 A gas occupies a volume of 28.4 mL at 725 mm Hg. What is the gas pressure if the volume is 35ml? • 588.3 mmHg One liter of a gas has a pressure of 150.00 kPa at 27.0°C. If the pressure increases to 600.0 kPa and the volume to half a liter, what would be the new temperature of the gas in Kelvin? • 600K A 50.0 mL sample of a gas is at 3.00 atm of pressure and a temperature of 298 K . What pressure would the gas be under at a volume of 25 mL and a temperature of 350 K? • 7 atm If you increase the pressure on a gas with a fixed temperature, what happens to the volume? Whose gas law is demonstrated by this example • It decreases • Boyle’s If you increase the Temperature on a gas with a fixed pressure, what happens to the volume? Whose gas law is demonstrated by this example • It increases • Charles’s Convert 2.5 atm to mm Hg • 2.5 x 760 = 1900 mm Hg Convert 2.5 atm to psi • 2.5 x 14.7 = 36.75 psi Convert 2.5 atm to kPa • 2.5 x 101.3 = 253.25 kPa