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1.Describe Law with a formula. 1.Describe Avogadro’s Law with a formula. 2.Use Law to determine either moles or volume 2.Use Avogadro’s Law to determine.

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Presentation on theme: "1.Describe Law with a formula. 1.Describe Avogadro’s Law with a formula. 2.Use Law to determine either moles or volume 2.Use Avogadro’s Law to determine."— Presentation transcript:

1 1.Describe Law with a formula. 1.Describe Avogadro’s Law with a formula. 2.Use Law to determine either moles or volume 2.Use Avogadro’s Law to determine either moles or volume 3.Describe the Law with a formula. 3.Describe the Ideal Gas Law with a formula. 4.Use Law to determine either moles, pressure, temperature or volume 4.Use the Ideal Gas Law to determine either moles, pressure, temperature or volume 5.Explain the Kinetic Molecular Theory

2 Equal volumes of gases at the same T and P have the same number of molecules. V = an V and n are directly related. twice as many molecules

3 Avogadro’s Law Summary  For a gas at constant temperature and pressure, the volume is directly proportional to the number of moles of gas (at low pressures). V = an a = proportionality constant V = volume of the gas n = number of moles of gas

4 Standard Molar Volume Equal volumes of all gases at the same temperature and pressure contain the same number of molecules. - Amedeo Avogadro

5 V1V1 n1n1 V2V2 n2n2 4.00 L 0.21 mol 7.12 L n2n2 0.37 mol total 0.16 mol added

6 Brings together gas properties. Can be derived from experiment and theory. BE SURE YOU KNOW THIS EQUATION! P V = n R T

7 Ideal Gas Law PV = nRT  P = pressure in atm  V = volume in liters  n = moles  R = proportionality constant  = 0.08206 L atm/ mol·   T = temperature in Kelvins Holds closely at P < 1 atm

8 Review of Kinetic Molecular Theory  Particles of matter are ALWAYS in motion  Volume of individual particles is  zero.  Collisions of particles with container walls cause pressure exerted by gas.  Particles exert no forces on each other.  Average kinetic energy  Kelvin temperature of a gas.

9  Real molecules have volume. The ideal gas consumes the entire amount of available volume. It does not account for the volume of the molecules themselves.  There are intermolecular forces. An ideal gas assumes there are no attractions between molecules. Attractions slow down the molecules and reduce the amount of collisions. › Otherwise a gas could not condense to become a liquid.

10 R is a constant, called the Ideal Gas Constant Instead of learning a different value for R for all the possible unit combinations, we can just memorize one value and convert the units to match R. R = 0.08206 R = 0.08206 L atm mol K

11 How much N 2 is required to fill a small room with a volume of 960 cubic feet (27,000 L) to 745 mm Hg at 25 o C? Solution Solution 1. Get all data into proper units V = 27,000 L V = 27,000 L T = 25 o C + 273 = 298 K T = 25 o C + 273 = 298 K P = 745 mm Hg (1 atm/760 mm Hg) = 0.98 atm P = 745 mm Hg (1 atm/760 mm Hg) = 0.98 atm And we always know R, 0.08206 L atm / mol K

12 RT RT RT RT How much N 2 is required to fill a small room with a volume of 960 cubic feet (27,000 L) to P = 745 mm Hg at 25 o C? Solution Solution 2. Now plug in those values and solve for the unknown. PV = nRT n = 1.1 x 10 3 mol (or about 30 kg of gas)

13 (5.6 atm)(12 L)(0.08206 atm*L / mol*K )(T) 200 K (4 mol)


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