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Chapter 11 KINETIC MOLECULAR THEORY OF AN IDEAL GAS. Particles do not attract or repel Move in straight line Collisions between particles are perfectly elastic G ases come close to ideal behavior at high temperature and low pressure. P pressure
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Chapter 11KINETIC MOLECULAR THEORYOF AN IDEAL GAS • Particles do not attract or repel • Move in straight line • Collisions between particles are perfectly elastic • Gases come close to ideal behavior at high temperature and low pressure
P pressure • T temperature (must be Kelvin) K = °C + 273) • n moles • V volume
Pressure = Force/Area • More collisions = more pressure • Standard (normal) atmospheric pressure • 760 mm of Hg = 1.00 atm = 101,325 Pa or 101.325 kPa (SI unit) =29.9 inches
P vs V (n and T constant)Boyle’s Law grc.nasa.gov/WWW/K-12/airplane/A...
V vs T (n and P constant)Charles’s Law V T grc.nasa.gov/WWW/K-12/airplane/A...
V vsn (P and T constant)Avogadro’s Law V n grc.nasa.gov/WWW/K-12/airplane/A...
P vsn(V and T constant)Dalton’s Law P moles (n) grc.nasa.gov/WWW/K-12/airplane/A...
P vs T (n and V constant) P T grc.nasa.gov/WWW/K-12/airplane/A...
Combined Gas Law • PV = constant • V/T = constant • P/n = constant • P/T = constant • P1V1/n1T1 = P2V2/n2T2 (when changing a variable) • PV/nT = constant (R) • PV = nRT (Ideal Gas Law) (when looking for one of the 4 variables)
P1V1/n1T1 = P2V2/n2T2 • Ex. If 5.00 liter of gas exert a pressure of 3.0 atm, what pressure will the gas exert if the volume is increased to 10.0 liters? (n and T are constant)
P1V1/n1T1 = P2V2/n2T2 • Ex. If 5.00 liter of gas exert a pressure of 3.0 atm, at a temperature of 25°C what pressure will the gas exert if the volume is increased to 10.0 liters and the temperature is increased to 200°C?
PV=nRT • R = ideal gas constant • R = PV/nT • PV R • atm Liters .0821 atmx L/mol x K • mm Hg Liters 62.4 mmHg x L/mol x K
PV=nRT • Ex. If .10 mole of a gas is added to a 2.0 liter container at a temperature of 25oC, what is the pressure exerted by the gas?
PV=nRT • Ex. What is the molar mass of a gas if .125 grams of the gas occupies .100 L when the temperature is 25oC and the pressure is.728 atm?
PV=nRT • Ex. What is the density of Helium at a pressure of 755 mm Hg and a temperature of 22.0oC?
Standard Temperature and PressureSTP • 0 C ( 273 K) • 1.0 atm ( 760 mmHg) • At STP 1.00 mole of any gas occupies a volume of 22.4 Liters (molar volume)
STP • Ex.If you have 100.0 liter of nitrogen gas at STP, how many moles of nitrogen gas do you have? • Ex.If you have 8.0 mole of carbon dioxide at STP, what volume will it occupy? • Ex. If you have 132 grams of carbon dioxide at STP, what volume will it occupy?
Stoichiometry and Gases • 2H2(g) + O2(g) ---> 2 H2O(g) • Ex.If 5.0 liters of hydrogen gas react, how many liters of oxygen gas are needed? (Gases are at the same temperature and pressure) • Ex.If 3.0 liters of hydrogen gas react, how many liters of water gas are produced? (Gases are at the same temperature and pressure)
Stoichiometry and Gases • 2H2(g) + O2(g) ---> 2 H2O(g) • ex. If 32.0 grams of hydrogen react at STP, what volume of oxygen will be needed? • ex. if 32.0 grams of hydrogen react at a pressure of .500 atm and a temperature of 20.0 oC what volume of oxygen will be needed?