Not so long ago, in a chemistry lab far far away… May the FORCE/area be with you

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

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

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

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

V1V1 n1n1 V2V2 n2n L 0.21 mol 7.12 L n2n mol total 0.16 mol added

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

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

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.

 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.

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 = R = L atm mol K

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 = 298 K T = 25 o C = 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, L atm / mol K

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)

Is It REALLY Worth Fighting Over???

University of Washington Chemistry Midterm Exam Question Is Hell exothermic or endothermic? Support your answer using the Ideal Gas Law. PV=nRT (P)ressure x (V)olume = number of particles of the gas (n) x the gas constant (R) x the (T)emperature of the gas One enterprising student wrote the following:

First we need to know how the number of particles (souls) are changing over time. Are the number of souls increasing or decreasing? What is the rate of souls entering Hell as compared to souls leaving Hell? Most religions teach that once in Hell, always in Hell, so lets assume that no soul is leaving Hell. Most religions also teach that if you do not abide by their religious teachings, you will go to Hell. So let’s assume that most souls are going to Hell.

Given the current birth and death rates, we can assume that the number of particles (souls) in Hell is increasing exponentially. According to the Ideal Gas Law, if n, the number of particles (souls) is increasing exponentially, for the temperature and pressure to stay the same, the volume must increase. There are therefore two possibilities:

1.If the volume of Hell is not expanding or expanding slower than the increase in particles (souls), then the temperature and pressure in Hell will increase until all Hell breaks loose. (Exothermic) 2.If the volume of Hell is expanding faster than the increase of particles (souls), then the temperature and pressure will drop until Hell freezes over. (Endothermic)

If we accept the postulate given to me by Ms. Krissy Jones during my freshman year that “it will be a cold day in Hell before I sleep with you,” and taking into account that I still have not succeeded in having sexual relations with her, than the second (2) possibility cannot be true. Therefore, I am sure that Hell is exothermic!

University of Washington Chemistry Midterm Exam Question Is Hell exothermic or endothermic? Support your answer using the Ideal Gas Law. PV=nRT The kid got an “A”!!!!!!!!!!!!!!!!!

(5.6 atm)(12 L)( atm*L / mol*K )(T) 2.0 x 10 2 K (4.0 mol)

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

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  Celcius temperature of a gas.

Try this One!!

mol mol mol x 10 3 mol 5. Not listed