Gases Notes (Ch. 12) A. The Characteristics of Gases 1) Gases have __________. An inflated basketball weighs ____ than a deflated basketball. 2) It is _______________ gases. 3) Gases _________________ completely. 1 mole of gas occupies 22.4L at STP eat 4) Different gases can move through each other rapidly w/o attracting to one another. Ex. diffusion 5) Gases exert ___________. The ________ of a gas depends on ____________. B. Kinetic Molecular Theory The distances separating gas particles are relatively _______. Gases exert pressure b/c their particles _________________into the wall of the containers. C. Kinetic Energy of Gas The average kinetic energy of gas particles depends on the temp. of the gas. So, kinetic energy ____ as temp ____. That means gas atoms/molecules move __________ as temp ______. D. How is pressure measured? Using a _________ Pressure = force exerted per unit area = _________
E. Units of Pressure SI unit of pressure = ___________ __________________– pressure exerted by the air in the atmosphere 1 atmosphere (atm) = 101.325 KPa 1 atm = 760 mm Hg = 760 torr Ms. Park
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F. Pressure Conversion (Show the work.) 2 atm = _______mm Hg = _____KPa G. Units of Temperature for Gas Laws STP = Standard Temp & Pressure ___________ & __________ For gas laws, temp. is in __________. Formula: K = C + 273 H. Gas Laws 1. __________ Law 2. __________Law 3. _____________Law 4. _____________Law 5. _________Law of Partial Pressure 6. _____________ Law I. Boyle’s Law Relationship between _______ & __________. The volume of gas is _________ proportional to pressure at constant temperature. Pressure _____ -> volume _____ Formula: P1V1 = P2V2
Scuba diving deeper into the ocean, the _______ pressure and the volume of lungs__________. Opposite as you ascend J. Boyle’s Law Example A gas at a pressure of 608 mm Hg is held in a container with a volume of 545 cm3. The volume of the container is then increased to 1065 cm3 without a change in temp. Calculate the new pressure of the gas.
Ms. Park
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K. Charles’ Law Relationship between ______ & _________ The volume of gas is _________ proportional to its Kelvin temperature at constant pressure Temp. _____ -> volume ______ Formula: V1/T1 = V2/T2 Formula: T1V2 = T2V1
Hot air rises and cold air sinks. Hot air has ______ volume than cold air so it is _____ dense. Things w/ low density float. L. Charles’ Law Example What will be the volume of a gas sample at 355 K if its volume at 273K is 8.57L? Assume that the pressure of the gas remains unchanged.
Learning Check 1.If pressure is doubled, what happens to volume? 2.If temperature is halved, what happens to volume? 3. Pressure and volume are ______ related. 4. Temperature and volume are _____ related. M. Combined Gas Law the relationship among _______, ________ and _________ of a fixed amount of gas. a combination of Boyle’s and Charles’ Law. Formula: P1V1 = P2V2 T1 T2 N. Combined Gas Law Example The volume of a gas at 780 mm Hg and 30 C is 500 mL. What volume would the gas occupy at STP?
Ms. Park
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O. Ideal Gas Law Formula: PV = nRT P = __________________(_______)_ V = __________________(_______)_ n = __________________________ T = __________________(_______)_ R = __________________________ = PV/nT = (1.00 atm)(22.4L) (1.00mol)(273K) R = 0.0821 L*atm/mol*K R= 8.314 L* kpa/mol*K P. Ideal Gas Law Example How many moles of a gas at 100 C does it take to fill a 1.00 L flask to a pressure of 1.50 atm?
Q. Dalton’s Law of Partial Pressure Total Pressure = ___________________________________________ Formula: Ptotal or total pressure = PA + PB + PC for a mixture of gases A, B and C R. Dalton’s Law Example If the total pressure of gases above the water in the container has a pressure of 3.5 atm and the pressure of the water vapor is 1.5 atm, what is the pressure of the oxygen gas?
S. Graham’s Law _________: movement of gas through a _____ opening _________: movement of gas from a ______ concentration area to a ___ concentration area. The ______ particles move ________.
