Kinetics

Question 1

Rate of conversion (J)

Answer 1

J = -(1/a)(dnA/dt) = -(1/b)/(dnb/dt)

A & B = -, C & D = +

Question 2

Reaction rate (r)

Answer 2

r = J/V = -(1/aV)(dnA/dt)

Question 3

Order of the reaction

Answer 3

The power to which the concentration of a reactant is raised

Question 4

Rate Law

Answer 4

r = d[P]/dt = k[A]^a[B]^b,

Expressed as a function of the reactant concentrations, set in square brackets, at constant temp

Question 5

Rate constant

Answer 5

k

Question 6

Partial orders

Answer 6

a & b

Question 7

Total order (n)

Answer 7

Sum of the partial orders

Question 8

First order reactions

aA -> products

Answer 8

r = k[A] = -(1/a)(d[A]/dt)

[A] = [A]o•e^(-ka•t)

ln([A]/[A]o) = -ka•t

Question 9

First order half life

Answer 9

t(1/2) = ln2/ka

Question 10

Second order reactions

Answer 10

2 types:
aA -> products

aA + bB -> products

Question 11

Second order reactions: type 1

Answer 11

d[A]/dt = -ka[A]^2

ka = a • k

Question 12

Second order half life:type 1

Answer 12

t(1/2) = 1/([A]o•ka)

Question 13

Second order reaction type: 2

Answer 13

r = k[A][B]

{1/(a[B]o-b[A]o}ln{([B]/[B]o)/([A]/[A]o)} = kt

Question 14

Nth order reaction

Answer 14

([A]/[A]o)^n-1 = 1+[A]^n-1•(n-1)•ka•t

t(1/2) = (2^n-1 - 1)/(n-1)•[A]o^n-1•ka

Question 15

Zeroth order reaction

Answer 15

r = d[A]/dt = -ka

[A] = -Ka•t + [A]o

t(1/2) = [A]o/2ka

Question 16

Reaction mechanism

Answer 16

The process by which the reaction occurs

Question 17

Reaction intermediates

Answer 17

Species that are formed in one step and consumed in another

Question 18

Stoichiometric number

Answer 18

The number of occurrences of a step

Question 19

Elementary reaction

Answer 19

Each step

Question 20

Initial rate method

Answer 20

Most common way for determining rate laws

Question 21

Collision theory

Answer 21

Reactants must collide to react. If temperature increases, so does the speed of the molecules and the frequency of collisions

Question 22

Activation energy

Answer 22

Energy that must be overcome for the reaction to occur

Question 23

Activated complex

Answer 23

A transition state where kinetic energy is stored as potential energy

Question 24

Arrhenius’s Equation

Answer 24

k = Ae^(-Ea/RT)

Question 25

Stark-Einstein Law

Answer 25

During a photochemical reaction, a photon may promote an electron to an excited electronic state where it is more likely to undergo s chemical reaction than in the ground state

Question 26

Vibrational relaxation

Answer 26

A* is usually produced in an excited vibrational state. Intermolecular collisions transfer part of this vibrational energy to other molecules, and A* relaxes to the lowest excited vibrational state

Question 27

Internal conversion

Answer 27

A molecule in its lowest vibrational state can make a radiation less transition to a different excited electronic state. For this process to occur A* and A’ must have the same energy. The molecule A’ is generally in a lower electronic state, but higher vibrational state than A*

Question 28

Internal conversion

Answer 28

The radiationless process where A’ and A are both singlet or triplet states

Question 29

Interstates crossing

Answer 29

A radiationless process where A* is a singlet electronic state and A*’ is a triplet electronic state

Question 30

Radiationless deactivation

Answer 30

Occurs when A* transfers its electronic excited energy to another molecule and returns to its ground state: A* + B -> A + B*

Question 31

Fluorescence

Answer 31

Occurs when light is emitted from an excited electronic state to a lower electronic state without spin change: dS = 0.

Question 32

Fluorescence

Answer 32

A* for can lose its electronic energy by spontaneously emitting a photon, which brings it to the ground state: A* -> A + hv

Question 33

Phosphorescence

Answer 33

Process is the emission of radiation from a triplet excited electronic state to a lower singlet state. Entropy > 0.

Question 34

Quantum yield

Answer 34

of moles reacting per unit time/ # of miles of light absorbed per unit time