Chemistry Reaction Rates

Front 1

Activated Complex

Back 1

An unstable, short-lived structure caused by the effective collision of particles.

Front 2

Activation Energy

Back 2

The minimum amount of kinetic energy particles must possess in order to undergo an effective collision.

Front 3

Catalyst

Back 3

A substance that increases the rate of a chemical reaction, but is not chemically changed at the end of the reaction.

Front 4

Chemical Equation

Back 4

A system for using chemical formulas and coefficients to indicate the types and rations of products and reactants involved in a chemical reaction.

Front 5

Chemical Reaction

Back 5

The conversion of substances into other substances that have different chemical properties.

Front 6

Collision Theory

Back 6

They hypothesis that in order to react, particles must collide at the proper orientation with more than a minimum amount of kinetic energy, known as the activation energy.

Front 7

Concentration

Back 7

Amount of a substance per unit of volume; for gases, this is the number of moles of the gas per liter.

Front 8

Elementary Process

Back 8

One of the steps of a reaction mechanism.

Front 9

Endothermic Process

Back 9

A process that absorbs heat.

Front 10

Energy

Back 10

The ability to perform work or to transfer heat.

Front 11

Enzyme

Back 11

A biological molecule that acts as a catalyst.

Front 12

Equilibrium

Back 12

A dynamic balance in which the rate of the forward process equals the rate of the reverse process.

Front 13

Exothermic Process

Back 13

A process that releases heat.

Front 14

Intermediate

Back 14

A particle thought to be present in the elementary processes of a reaction mechanism. Intermediates do not appear in the balanced equation of the reaction because they are both produced and consumed in the course of the reaction.

Front 15

Kinetic Energy

Back 15

Energy associated with motion.

Front 16

Kinetics

Back 16

The study of reaction rates and mechanisms.

Front 17

Mole

Back 17

6.02 X 10^23

Front 18

Order

Back 18

For an individual reactant, the exponent of the reactant's concentration in the rate law; for an overall reaction, it is the sum of the exponents of all concentrations in the rate law.

Front 19

Potential Energy

Back 19

Energy that is stored due to position, chemical bonds, or other factors.

Front 20

Product

Back 20

A substance resulting from a chemical reaction.

Front 21

Rate

Back 21

Amount of change per unit of time.

Front 22

Rate Constant

Back 22

The proportionality in a rate law expression, which is symbolized by k. The rate constant is temperature dependent.

Front 23

Rate-Determining Step

Back 23

A reaction mechanism's slowest elementary process. This step determines the overall rate of a reaction.

Front 24

Rate Law Expression

Back 24

A mathematical expression relating the concentrations of reactants to a reaction rate.

Front 25

Reactant

Back 25

A substance present at the start of a chemical reaction.

Front 26

Reactant Mechanism

Back 26

The set of elementary processes that describes a chemical reaction at the molecular level.

Front 27

Reaction Rate

Back 27

The change in concentration of a reactant or product divided by time, normalized by dividing by the stoichiometric coefficient of the reactant or product in the balanced equation.

Front 28

Stoichiometry

Back 28

The techniques employed for calculating the relationship of the quantities of reactants and products in chemical reactions and for balancing chemical equations.

Front 29

Transition State

Back 29

The point at which the activated complex exists, as reactants turn into products.