Chapter 12 Vocab

Question 1

Chemical Kinetics

Answer 1

The area of chemistry concerning reaction rates

Question 2

Reaction rate

Answer 2

The change in concentration of a reactant or a product per unit time

Question 3

Instantaneous rate

Answer 3

The rate at some instance in time

Question 4

Rate law

Answer 4

An expression that shows how the rate of reaction depends on the concentration of reactants

Question 5

Rate constant

Answer 5

The proportionality constant in the relationship between reaction rate and reactant concentrations

Question 6

Order

Answer 6

The positive or negative exponent determined by experiment of the reactant concentration in a rate law

Question 7

Differential rate law

Answer 7

An expression that gives the rate of a reaction as a function of concentrations often called the rate law

Question 8

Integrated rate law

Answer 8

And expression that shows the concentration of reacting as a function of time

Question 9

Method of initial rates

Answer 9

Finding the order by running a controlled reaction only changing the concentration

Question 10

Initial rate

Answer 10

The instantaneous rate at the start of the reaction

Question 11

Overall reaction order

Answer 11

The reaction order of the whole compound/equation

Question 12

1st order reaction

Answer 12

Increases at a rate of only one reactants concentration

Question 13

Half life of a reactant

Answer 13

The time required for a reaction to reach half of its original concentration

Question 14

Reaction mechanism

Answer 14

The series of elementary steps involved in a chemical reaction

Question 15

Intermediate

Answer 15

A species that is neither a reactant or product but that is formed and consumed in the reaction sequence

Question 16

Elementary step

Answer 16

Reaction whose rate law can be written from its molecularity

Question 17

Molecularity

Answer 17

The number of species that must collide to produce the reaction represented by an elementary step in a reaction mechanism

Question 18

Unimolecular step

Answer 18

A reaction involving only one molecule

Question 19

Bimolecular step

Answer 19

A reaction involving the collision of two molecules

Question 20

Termolecular step

Answer 20

A reaction involving the simultaneous collision of three molecules

Question 21

Rate determining step

Answer 21

The slowest step in a reaction mechanism the one determining the overall rate

Question 22

Collision model

Answer 22

A model based on the idea that molecules most collide to react used to account for the observe characteristics of reaction rates

Question 23

Activation energy

Answer 23

The threshold energy that must be overcome to produce a chemical reaction

Question 24

Activated complex

Answer 24

The arrangement of Adams found at the top of the potential energy barrier as a reaction proceeds from reactants to products

Question 25

Transition state

Answer 25

The state corresponding to the highest energy along the reaction coordinate

Question 26

Molecular orientations

Answer 26

Orientations of molecules during collisions some of which can lead to reaction while others cannot

Question 27

Steric factor

Answer 27

The factor that reflects the fraction of collisions with orientations that can produce a chemical reaction

Question 28

Arrhenius equation

Answer 28

The equation representing the rate constant as k=Ae^-Ea/RT Where A represents the product of the collision frequency in the steric factor and e^-Ea/RT Is the fraction of collisions with sufficient energy to produce a reaction

Question 29

Enzyme

Answer 29

A large molecule usually a protein that catalyzes biological reactions

Question 30

Catalyst

Answer 30

A substance that speeds up a reaction without being consumed

Question 31

Homogeneous catalyst

Answer 31

A reaction where the catalyst is the same phase as the reactant

Question 32

Heterogeneous catalyst

Answer 32

When the catalyst is a different phase from the reactant

Question 33

Adsorption

Answer 33

The collection of one substance on the surface of another