Topic 2b- kinetics (reaction mechanisms)

Question 1

Does reaction rate increase with temp

Answer 1

yes

Question 2

activation energy

Answer 2

minimum amount of energy required for reaction
-also known as the transition state on the graph

Question 3

what happens at activated complex/ transition state

Answer 3

reactants rotate into products

Question 4

bigger activation/ larger kj will be faster or slower?

Answer 4

slower

Question 5

arrhenius equation

Answer 5

ln k= -ea/RT + Ln A

-RT is 8.314 because kj

Question 6

how to find ea (activation energy)

Answer 6

-slope x R

Question 7

what are our indicators for arrhenius

Answer 7

temp and rate

Question 8

what is the actual process called going from reactants to products

Answer 8

reaction mechanism

-includes elementary reaction or elementary process

Question 9

molecularity

Answer 9

how many molecules are involved in the process (how many products: rate law exp, ratio count/amount of reactants)

-eg. unimolecular, bimolecular, thermomolecular

Question 10

when crossing out reactions between each step what do we need to make sure off

Answer 10

they are on opposite sides of the arrows and it determines intermediate

Question 11

Ea1 will always be _________ than E2

Answer 11

greater

Question 12

because thermomolecular are rare, this rate law suggests

Answer 12

two step reaction mechanism

Question 13

what determines the rate

Answer 13

slow step

Question 14

forward and reverse reactions (equilibrium) will have what step first

Answer 14

fast first

Question 15

relationship between forward and reverse

Answer 15

they are equal to each other

Question 16

SN1 and SN2 step

Answer 16

1: two step
2: one step

Question 17

catalysts increase what

Answer 17

the rate of reaction by decreasing activation energy

Question 18

enzymes

Answer 18

-bio catalyst
-lock and key method
-position in active site can help break down more

Question 19

rate limiting step isnt usually known, what do we use

Answer 19

steady state approx

Question 20

reaction rate steps

Answer 20

-cross out and find intermediates
-write consuming rate laws (should be 3: 1st prod, 2nd prod, and both intermediates in one)
-formula of IM = to one not solving for
-isolate the [ ] and divide to other side
-use the formula above and insert for the [ ] your solving for, the other [ ] rate law needs from 2nd prod needs to be put on top as well as k2 goes back in

Question 21

whats the formula for two point arrhenius

Answer 21

Ln k2/k1= -ea/R (1/t2 - 1/t1)

Question 22

our over all rate law will be found in

Answer 22

slow step

Question 23

if slow step isnt know, what do we need to do

Answer 23

steady state aprox

Question 24

rate laws will have to do with

Answer 24

reactant side only (consuming)
k-1 backwards

Question 25

when a reaction says it triples or doubles what do we do? for triples what does it go over

Answer 25

-ln 2, ln 3 k3/k1

Question 26

we will usually solve and take out _______ for finding fast and slow

Answer 26

k-1, intermediate taken off after being brought out -intermediates will NOT be in rate law

Question 27

for two steps with k3, how to we determine rate law

Answer 27

-if slow in first, we can determine right away -if slow is in 2nd or 3rd and we have intermediate, we need to use steady state approx -if we don't know, we need to use steady state approx