Chemical Kinetics Flashcards

Flashcards on Chemical Kinetics

Chemical Kinetics

The branch of chemistry dealing with reaction rates, factors affecting rates, and reaction mechanisms.

Rate of Reaction

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

Rate Law

Expression relating the rate of a reaction to the concentration of reactants.

Rate Constant (k)

Proportionality constant relating molar concentration of reactants to the rate of a chemical reaction

energy, orientation

Collision theory states that in order to react, molecules must collide with sufficient and proper .

Activation energy

Energy needed to break old bonds

10^-12

Fast reactions complete in less than __ seconds.

Moderate reactions

Reactions intermediate between slow and fast reactions.

Homogeneous reaction

Occurs when the reaction takes place in only one phase, either gas or liquid mixture.

Heterogenous reaction

Occurs when the reaction taking place in two or more phases.

Catalyst

A substance that increases the rate of a reaction without being consumed.

Rate Law Equation

Mathematical expression describing the relationship between the rate and reactant concentrations.

Molecularity of a Reaction

Number of reactant molecules involved in a single elementary reaction step.

Unimolecular reaction

Elementary reaction involving a single reactant molecule.

Bimolecular reaction

Elementary reaction involving two reactant molecules.

Trimolecular reaction

Elementary reaction involving three reactant molecules.

Order of Reaction

Number of reacting molecules whose concentrations alters as a result of chemical change.

Zero Order Reaction

Reaction whose rate is constant and independent of reactant concentrations.

First Order Reaction

Reaction whose rate depends on the concentration of only one reactant.

Pseudo-First Order Reaction

Reaction that appears to follow first-order kinetics under certain conditions.

Second-Order Reaction

Reaction whose rate is proportional to the square of the concentration of one reactant or the product of two reactants.

Third Order Reactions

Reaction whose rate depends on the concentration of three reactant molecules or on the cube of a single reactant’s concentration.

Reaction Mechanism

Step-by-step description of what occurs during a reaction on the molecular level.

Rate-Determining Step

Slowest step in a reaction mechanism, determining the overall reaction rate.

Half life

t½ α 1/[]^n-1 is the equation for the _ method for finding the order of a reaction