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22 Cards in this Set
- Front
- Back
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mean free path
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distance travelled by gas molecule between collisions
v small, but with rapid movement = 2.5 billion collisions per second |
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STP
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0*C
1 atm |
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STP
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0*C
1 atm |
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kinetic molecular theory
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ideal gas:
1. molecules have zero volume 2. exert no force other than repulsive from collisions 3. completely elastic collisions 4. avg KE is proportional to temp of gas PV=nRT |
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R
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universal gas constant
0.08206 L atm K-1 mol-1 8.314 J K-1 mol-1 |
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standard molar volume
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22.4 L at STP (ideal)
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partial pressure
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Pa=XaPtotal
Xa=mole fraction (moles gas a/moles total) |
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Daltons law
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total partial pressure is sum of partial pressures
P tot= P1+P2+P3... |
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avg KE of a mole of gas molecs
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KE=3/2RT
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Grahams law
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v1/v2 = root m2/root m1
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effusion
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spread of gas from high pressure to low pressure thru a pin hole
effusion rate1/rate2=rootM2/rootM1 |
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diffusion
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spread of one gas into another gas or into empty space
much slower than rms b/c collide with each other and with other molecs as diffuse diffusion rate 1/rate2=rootM2/rootM1 |
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real gases
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Vreal>Videal (bc real gases do have volume, so must be added to ideal volume)
Preal<Pideal (pulled inward by forces before hit wall, so not hitting with as much force) deviate above 10atm and temps near boiling points (cold, close together) n=PV/RT (should be 1 with ideal, if greater, volume deviates more; if less than one, intermolec forces deviate more) |
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kinetics vs thermodynamics
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k= movement towards equilibrium (rxns and rates)
thermod= what equilibrium looks like |
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reaction components/necessities
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collision
activation E spatial orientation all need to be met for the reaction to go |
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rate of reaction
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tells us how much the concentration of a reactant or product is changing
usually in terms of molarity per second (mol/L/s) affected by temp, pressure and concentration of certain substances (pressure usually small enough to be ignored) k = rate constant |
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rate law
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forward rate=k[A]^a[B]^b
a and b are ORDER of each resepective reactant a+b is OVERALL ORDER of rcn have to determine by experiment |
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zeroth order reaction
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plot of [A] with respect to t = straight line, slope= -k
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first order rxn
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rate=k[A]
graphed ln[A] with t = straight line, slope -k constant half life INDEPENDENT of [A] |
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irreversible 2nd order rxn
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2A-->products
rate=k[A]^2 plotting 1/[A] and time = straight line with slope k half life is DEPENDENT on [A] EACH CONSECUTIVE HALF-LIFE IS 2X AS LONG AS THE LAST |
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second order reaction
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A + B --> products
rate=k[A][B] random graphs, random half lifes |
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irreversible 3rd order rxn
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3A--> products
rate=k[A]^3 1/2[A]^2 vs t is straight line with slope k |
