Chemical kinetics

Question 1

The actual series of steps through which a reaction occurs

Answer 1

mechanism

Question 2

A component in the reaction that is neither a reactant or product

Answer 2

intermediate

Question 3

the slowest step in the mechanism

Answer 3

rate-determining step

Question 4

The change of concentration of reactant or product with respect to time

Answer 4

reaction rate

Question 5

The exponents of the rate law are equal to the __ ___ of the ___ ___.

Answer 5

stoichiometric coefficients, rate-determining step

Question 6

A zero order reaction has a ___ rate, which is ___ of the reactants’ concentrations.

Answer 6

constant, independent

Question 7

A first order reaction has a rate proportional to the concentration of ___ ____.

Answer 7

one reactant

Question 8

A second order reaction has a rate proportional to the product of the concentration of ___ __ or to the square of the concentration of a ___ __

Answer 8

two reactants, single reactant

Question 9

For a reaction to occur, molecules must ___ with each other. The collision theory of chemical kinetics states that the rate of a reaction is proportional to the ___ ___ ____ ___ ___ between the reacting molecules. Reaction rates almost always ___ with increasing temperatures and ____ with decreasing temperatures.

Answer 9

collide, number of collisions per second, increase, decrease

Question 10

An ___ _, is one that leads to the formation of products, and only occurs if the molecules collide with the correct ____ and sufficient ____ to break __ ___ and form new ones. The minimum energy of collision necessary for a reaction to take place is called the ___ __ or the ___ ___. only a ___ of colliding particles have enough kinetic energy to exceed the activation energy.

Answer 10

effective collision, orientation, force, existing bonds, activation energy, energy barrier, fraction

Question 11

When molecules collide with sufficient energy, they form a ___ ___ in which the old bonds are weakened and new bonds are beginning to form. This then ___ into products, and the new bonds are __ ___.

Answer 11

transition state, dissociates, fully formed

Question 12

The transition state, also called an ___ ___, has greater energy than either the reactants or products. The ___ __ is required to bring the reactant to this energy level. Once an activated complex is formed, it can either ___ into products or ___ to reactants with any additional __ ___. Transition states are distinguished from ____ in that they do not have a __ ___.

Answer 12

activated complex, activation energy, dissociate, revert, energy input, intermediates, finite lifetime

Question 13

A ___ __ ___ illustrates the relationship between the activation energy, the __ of the reaction and the potential energy before and after the reaction. the __ ___ for the reaction is the difference in potential energy of the products and and reactants.

Answer 13

potential energy diagram, heats, enthalpy change

Question 14

The greater the ___ of the reactants (more particles per volume), the greater the number of ___ __ per unit time, so the reaction rate will increase for all but ____ ___.

Answer 14

concentrations, effective collisions, zero-order reactions

Question 15

Since the temperature of a substance is a measure of the particles’ ___ __ ___, increasing the temperature results in the proportion of molecules having energies greater than the __ __ will increase with increasing temperature,

Answer 15

average kinetic energy, activation energy

Question 16

Due to differences in ___ ___ and other stabilizing factors, certain reactions proceed more rapidly in ___ __, whereas other reactions proceed more rapidly in_____ ____. The ___ of the medium can also have a significant effect.

Answer 16

intermolecular forces, aqueous solution, nonpolar solvents, state

Question 17

___ are substances that increase reaction rate without being consumed. They do this by lowering the ___ ___. ____ are biological catalysts. Catalysts may increase the ___ ___ ___ between the reactants, change the relative ___ of the reactants to make a higher percentage effective, donate ___ ___ to the reactants, or reduce ___ ___ within reactant molecules. Both the __ and ___ rates are increased by the catalyst, and thus the catalyst causes a reaction to proceed more quickly to ____

Answer 17

catalysts, activation energy, enzymes, frequency of collision, orientation, electron density, intramolecular bonding, forward, reverse, equilibrium