Kinetics

Question 1

Rate Law

Answer 1

Is the relationship between rate and concentration

- Rate is proportional to [A]

Question 2

Rate Constant

Answer 2

Is the proportionality constant (K) in the Rate Law

- Rate = k [A]

Question 3

Third Order

Answer 3

When the overall reaction order in the rate law is 3

• rate is 3rd order in a single reactant
• rate is 2nd order in one reactant and 1st in another
• rate is 1st order in each of 3 reactants

Question 4

Second Order

Answer 4

When the overall reaction order in the rate law is 2
Rate is proportional to the square of the concentration (factor of 4)
- The rate is 2nd order in a single reactant
- the rate is 1st order in each of 2 reactants

Question 5

First Order

Answer 5

When the overall reaction order in the rate law is 1.
Rate is directly proportional to the concentration of a reactant
- 1st order in a single reactant

Question 6

Half Life

Answer 6

The amount of time it takes for the concentration of the reactants to fall by half.

Question 7

Transition State

Answer 7

Is the point of highest energy in an elementary reaction, between reactants and products - top of activation energy, is an unstable state

Question 8

Heterogeneous Catalyst

Answer 8

A catalyst which is in a different phase to the reactants

e.g. Solid catalyst and gas reactants

Question 9

Catalyst

Answer 9

A substance which speeds up a reaction without being consumed in the overall process.
The catalyst provides an alternative reaction pathway of lower activation every.

Question 10

Homogenous Catalyst

Answer 10

Catalyst working in the same phase as the reactants

e.g. A mixture of two solutions

Question 11

Rate of Reaction

Answer 11

How many times the reaction occurs per second

- change in concentration / Change in time

Question 12

Average Rate of Reaction

Answer 12

Is the change in concentration over a period of time in the reaction

Question 13

Instantaneous Rate of Reaction

Answer 13

The rate of Reaction of one specific moment in time

Question 14

Initial Rate of Reaction

Answer 14

Rate of Reaction when only reactants are present and t=0

Question 15

Reaction Order

Answer 15

Gives indication to the effect of concentration on the instantaneous rate of Reaction
e.g. zero order Reaction would show the rate is independent of concentration

Question 16

[R]=[R]o e^(-kt)

Answer 16

First Order reactions

ln [R] = ln [R]o - kt

ln[R] over time will show a straight line with the slope being -k

Question 17

1/[R] = 1/[R]o + kt

Answer 17

Second Order Reactions

1/[R] against time will show a straight line of +k

Question 18

t(1/2) = ln2/ k

[R]/[R]o = 1/2 = e(-kt(1/2))

Answer 18

First Order half Life equations

ln[R] = ln[R]o - kt

Question 19

t(1/2) = 1/[R]ok

Answer 19

Second Order half Life equation

Question 20

Elementary Reaction

Answer 20

Reaction where reactions meet and collide forming products in one step

Question 21

Unimolecular elementary reaction

Answer 21

A single molecule reacting by itself

Question 22

Bimolecular elementary Reaction

Answer 22

Reaction where two molecules meet and react

Question 23

Termolecular elementary Reaction

Answer 23

Reaction where 3 molecules meet and react

Question 24

k = Ae (-Ea/RT)

Answer 24

Arrhenius Equation
- gives the relationship for the temperature dependence of the reaction rate Constant

ln k = ln A (-Ea/RT)

Question 25

Rate Determining Step

Answer 25

The slow step in the mechanism
This will determine the rate law with reactants added - cannot have intermediates in rate Law can switch them using equilibrium Constant