Chemical Kinetic and Equilibrium

Question 1

what is the rate law?

Answer 1

rate = K[A]^x[B]^y
where x and y are coefficients of reactants A and B
K = rate constant

Question 2

what is the overall rate of rxn?

Answer 2

x+y

determined experimentally

Question 3

zero order rxn?

Answer 3

constant rate

independent of conc of reactants

Question 4

first order rxn?

what;s an example of first order?

Answer 4

rate is proportional to conc of 1 reactant

half life

Question 5

2nd order

Answer 5

K[A]2 or K[A][B]

Question 6

mixed order

Answer 6

fractional order (fractional exponent)

Question 7

what is the collision theory of chem kinetics?

Answer 7

rate of rxn is proportional to numbe of collisions per sec

Question 8

effective collision

Answer 8

collision of reactants that lead to formation of products

Question 9

rate of collision r =

Answer 9

r = fz

f is fraction of effective collisions
z is # of collisions

Question 10

transition state

Answer 10

mcules that collide with enough E go into transition state, bonds are weakened, new bonds begin to form

Question 11

what factors influence rxn rate?

Answer 11

1. conc of reactants…higher conc is high rate
2. temp…higher temp is higher rate
3. medium…change medium, change rate
4. catalyst…rate inc, Ea dec

Question 12

homogenous vs heterogeneous catalysts

Answer 12

homo-same phase as reactants

hetero-different

Question 13

forward rxn rate
reverse rxn rate

Eq. constant, Kc =

Answer 13

Rf = Kf[A]x
Rr = Kr[B][C]

Kc = Kf/Kr

Question 14

what is the law of mass action?

aA + bB –> cC + dD

Answer 14

rxns with more than 1 step:

Keq = [C]c[D]d/[A]a[B]b

[Products]/[reactants]

Question 15

what is reaction quotient Q?

Answer 15

measure of the degree to which rxn has gone to completion

Q=Kc at eq

Question 16

what are the characteristic of Keq?

Answer 16

Pure solids and liquids not in the expression
Is given for a given system of given T
If Keq is larger than 1, more products than reactants
If small, like .1, more reactants
If Keq ~ 1, same product and reactants

Question 17

when P is system increases, which side will rxn shift?

Answer 17

side with less moles

Question 18

If V increases in system, which way will rxn shift?

Answer 18

if V inc, P dec, so shift to side with more moles

Question 19

In a zero order rxn, what does rate =?

Answer 19

rate = K!

Rate = K[A]^0
rate = K(1)

Question 20

what is the half life equation?

Answer 20

1/2 = e^(-kt)

Take ln of each side

Question 21

are catalysts consumed in a rxn?

Answer 21

no

Question 22

does a catalyst change the Keq?

Answer 22

no