Unit 3

Question 1

The speed at which a chemical reaction occurs

Answer 1

Reaction rate

Question 2

expresses the relationship of the rate of a reaction to the rate constant (k) and the concentration of the reactants raised to certain powers

Answer 2

Rate laws

Question 3

is the time it takes for the centration of a reactant to drop to one-half of its initial value. If a reaction has a short half-life, it is a fast reaction

Answer 3

Half life

Question 4

is the area of chemistry in which reaction rates are studied. Factors that affect reaction rate are the physical state of reactants; concentration; temp; and the presence of catalysts

Answer 4

Chemical kinetics

Question 5

are usually expressed as changes in concentration per unit time: Typically, for reactions in solution, rates are given in unit of molarity per second (M/s. For most reactions, a plot of molarity versus time shows that the rate slows down as the reaction proceeds

Answer 5

Reaction rates

Question 6

is the slop of a line drawn tangent to the concentration-versus-time curve at a specific time.

Answer 6

Instantaneous rate

Question 7

The quantitative relationship between rate and concentration is expressed by a

Answer 7

rate law

Question 8

k [reactant 1]^m[reactant 2]^n=

Answer 8

Rate

Question 9

The constant k in the rate law is called the

Answer 9

rate constant

Question 10

the exponents m, n and so forth are called

Answer 10

reaction orders

Question 11

The sum of the reaction orders gives the

Answer 11

overall reaction order

Question 12

the rate is proportional to the concentration of a single reactant raised to the first power

Answer 12

first-order reaction

Question 13

is one for which the overall reaction order is 2

Answer 13

second-order reaction

Question 14

is one for which the overall reaction order is 0.

Answer 14

Zero-order reaction

Question 15

assumes that reactions occur as a result of collusions between molecules, helps explain why the magnitudes of rate constants increase with increasing temp.

Answer 15

collision model

Question 16

The minimum energy required for a reaction to occur is called the

Answer 16

activation energy

Question 17

is the highest energy arrangement in the pathway from reactants to products.

Answer 17

activated complex or transition state

Question 18

details the individual steps that occur in the course of a reaction

Answer 18

reaction mechanism

Question 19

(steps) has a well-defined rate law that depends on the number of molecules (the molecularity) of the step

Answer 19

elementary reactions

Question 20

Unimolecular, bimolecular, termolecular

Answer 20

elementary reactions

Question 21

are very rate

Answer 21

termolecular

Question 22

is produced in one elementary step and is consumed in a later elementary step, therefore it does not appear in the overall equation for the reaction

Answer 22

intermediate

Question 23

When a mechanism has several elementary steps, the overall rate is limited by the slowest elementary step, called the

Answer 23

rate-determining step

Question 24

is a substance that increases the rate of a reaction without undergoing a net chemical change itself

Answer 24

catalyst

Question 25

is one that is in the same phase as the reactants

Answer 25

homogeneous catalyst

Question 26

has a different phase from the reactants

Answer 26

heterogeneous catalyst

Question 27

(binding), of a reactant at specific sites on the surface makes bond breaking easier, lowering the activiation energy

Answer 27

adsorption

Question 28

large protein molecules that usually catalyze a very specific reaction

Answer 28

enzymes

Question 29

The specific reactant molecules involved in an enzymatic reaction are called

Answer 29

substrates

Question 30

the site of the enzyme where the catalysis occurs is called the

Answer 30

active site

Question 31

substrate molecules bind very specifically to the active site of the enzyme, after which they can undergo reaction

Answer 31

lock-and-key model

Question 32

4 factors of chemical reaction

Answer 32

- physical state - concentration - Temp - presence of catalyst

Question 33

The number of molecules that participate in an elementary reaction is called

Answer 33

Molecularity

Question 34

single molecule

Answer 34

unimolecular

Question 35

two molecule

Answer 35

bimolecular

Question 36

Three molecule

Answer 36

termolecular