TOPIC 8- CHEMICAL KINETICS

Question 1

the area of chemistry concerned with the
speeds, or rates, at which a chemical reaction occurs.

Answer 1

Chemical Kinetics

Question 2

refers to the rate of a reaction, or the reaction rate which is the change in the concentration of a product or reactant with time.

Answer 2

Kinetics

Question 3

What are the factors affecting reaction rate?

Answer 3

1. Concentration
2. Physical State
3. Temperature
4. Catalysts

Question 4

Most chemical reactions proceed faster if the concentration
of one or more of the reactants is

Answer 4

increased

Question 5

The more ready molecules collide with each other,

Answer 5

the more rapid they react

Question 6

Raising the temperature increases the

Answer 6

number and the energy of collisions

Question 7

Molecules must collide with enough energy to

Answer 7

react

Question 8

are agents that increase reaction rates without being
used up.

Answer 8

catalysts

Question 9

Catalysts catalyze chemical reaction rates by lowering the

Answer 9

activation energy

Question 10

is the energy needed for the chemical
reaction to begin.

Answer 10

activation energy

Question 11

is a change in some variable per unit time.

Answer 11

Rate

Question 12

is the change in concentrations of reactants or
product in a chemical reaction per unit time.

Answer 12

Reaction Rate

Question 13

Reactant concentration decrease as

Answer 13

solution concentration increase

Question 14

is the reaction rate between any two intervals.

Answer 14

Average Rate

Question 15

is the reaction rate at a specific point in
time.

Answer 15

Instantaneous rate

Question 16

is the instantaneous rate at the moment the
reactants are mixed.

Answer 16

Initial rate

Question 17

expresses the rate as a function of reactant
concentrations and temperature.

Answer 17

rate law

Question 18

are used to measure the concentration
of a reactant or product that absorbs (or emits) light of a narrow
range of wavelengths.

Answer 18

spectrometric methods

Question 19

are used to measure the rate when
nonionic reactants for ionic products, or vice versa since the
conductivity of the solution changes over time.

Answer 19

Conductometric methods

Question 20

are used if the reaction involves a
change in the number of moles of gas.

Answer 20

Manometric methods

Question 21

In manometric methods, The rate can be determined from the change in ___________
(at constant volume and temperature) over time.

Answer 21

pressure

Question 22

are used to measure the rates of
slow reactions, or of those that can be easily slowed.

Answer 22

Direct Chemical Methods

Question 23

A small, measured portion called _______ of the reaction
mixture is removed, and the reaction in this portion is
stopped by rapid cooling.

Answer 23

aliquot

Question 24

We can
determine the reaction order and then the rate constant of the
reaction from

Answer 24

reactant concentration

Question 25

Note that the exponents of L and mol in the unit of the rate constant is equal to the

Answer 25

overall reaction order minus one

Question 26

enable us to calculate the rate of a reaction from the rate constant and reactant concentrations

Answer 26

Rate law expressions

Question 27

The rate laws can also be used to determine the concentrations of reactants at anytime during a reaction by employing different forms,

Answer 27

integrated rate laws

Question 28

These are reactions whose rate depends on the reactant concentration raised to the first power.

Answer 28

First Order Rate Laws

Question 29

are reactions whose rate depends on the concentration of one reactant raised to the second power or on the concentrations of two different reactants, each raised to the first power.

Answer 29

Second Order Rate Laws

Question 30

These are reactions whose rate is a constant, independent of reactant concentration.

Answer 30

Zeroth Order Rate Laws

Question 31

time required for the reactant concentration to reach half its initial value.

Answer 31

Half-life of a reaction

Question 32

is a constant, independent of reactant concentration.

Answer 32

Half-life of a First-Order Reaction

Question 33

does depend on reactant concentration and the half-life is inversely proportional to the initial concentration.

Answer 33

Half-life of a second-order reaction

Question 34

is directly proportional to the initial reactant concentration.

Answer 34

Half-Life of a Zero-Order Reaction

Question 35

Most chemical reactions occur by a series of steps called the

Answer 35

reaction mechanism

Question 36

a species that is canceled from both sides of the reaction (not a reactant or product.)

Answer 36

intermediate

Question 37

Each of these two reactions is called an

Answer 37

elementary Step

Question 38

The sequence of elementary steps that leads to product formation is the

Answer 38

reaction mechanism

Question 39

is always formed in an early elementary step and consumed in a later elementary step.

Answer 39

intermediate

Question 40

is the number of molecules reacting in an elementary step.

Answer 40

Molecularity of a reaction

Question 41

elementary step with 1 molecule

Answer 41

Unimolecular reaction

Question 42

elementary step with 2 molecule

Answer 42

Bimolecular reaction

Question 43

elementary step with 3 molecule

Answer 43

Termolecular reaction

Question 44

The rate law of a reaction mechanism is derived from the slowest step called

Answer 44

rate-determining step

Question 45

A reaction mechanism must satisfy the following:

Answer 45

1. The sum of the elementary steps must give the overall balanced equation for the reaction. 2. The mechanism must agree with the experimentally determined rate law.

Question 46

is built around the central idea that molecules must collide to react.

Answer 46

Collision model

Question 47

proposed the existence of the activation energy that must be overcome to produce a chemical reaction.

Answer 47

Svante Arhenius

Question 48

The higher the activation energy, the ___________________ at a given temperature.

Answer 48

slower the reaction

Question 49

Many collisions, even though they have the required energy, still do not produce a reaction due to

Answer 49

molecular orientation during collisions

Question 50

Two requirements must be satisfied for reactants to collide:

Answer 50

1. The collision must involve enough energy to produce the reaction; that is, the collision energy must equal or exceed the activation energy. 2. The relative orientation of the reactants must allow formation of any new bonds necessary to produce products.

Question 51

what are the types of catalysts?

Answer 51

1. Homogeneous catalyst 2. Heterogeneous catalyst

Question 52

is one that is present in the same phase as the reacting molecules.

Answer 52

Homogeneous Catalyst

Question 53

exists in a different phase, usually as a solid.

Answer 53

Heterogeneous Catalyst

Question 54

refers to the collection of one substance on the surface of another substance

Answer 54

Adsorption

Question 55

refers to the penetration of one substance into another.

Answer 55

Absorption