Chemical Kinetics: Temperature, Activation Energy, and Mechanisms

Temperature

Measure of average kinetic energy of molecules.

Reaction Rate

Speed at which reactants convert to products.

Collision Model

Reactions require molecular collisions to occur.

Activation Energy (Ea)

Minimum energy needed for a reaction to proceed.

Transition State

High-energy state during a chemical reaction.

Activated Complex

Species present at the transition state.

Reaction Coordinate Diagram

Visual representation of energy changes in reactions.

Maxwell-Boltzmann Distribution

Distribution of molecular kinetic energies at a temperature.

Frequency Factor (A)

Likelihood of effective collisions in a reaction.

Arrhenius Equation

Mathematical relationship between rate constant and activation energy.

Natural Logarithm

Logarithm to the base e, used in Arrhenius Equation.

Elementary Reaction

Single step in a reaction mechanism.

Molecularity

Number of molecules involved in a reaction step.

Rate Law

Expression relating reaction rate to reactant concentrations.

Rate-Determining Step

Slowest step in a multistep reaction mechanism.

Catalyst

Substance that increases reaction rate by lowering activation energy.

Enzyme

Biological catalyst that speeds up biochemical reactions.

Induced Fit Mechanism

Model where substrate binding changes enzyme shape.

Kinetic Energy

Energy of motion, related to temperature.

Energy Barrier

Energy threshold that must be overcome for reaction.

Reaction Mechanism

Sequence of steps converting reactants to products.

Intermediate

Species formed during the reaction but not in products.

Temperature Increase Effect

Higher temperature increases reaction rate and energy distribution.

Slope of ln k vs. 1/T

Used to calculate activation energy from experimental data.

Dotted Line in Distribution

Represents activation energy in Maxwell-Boltzmann distribution.

Broadening of Distribution

Wider range of energies at higher temperatures.

Collision Orientation

Correct alignment needed for effective molecular collisions.

Energy Changes

Variations in energy throughout a chemical process.

Chemical Reaction

Process where reactants transform into products.

Fast Step

Step in a reaction mechanism that occurs quickly.

Slow Step

Step in a reaction mechanism that limits overall rate.

Reactants and Products

Substances consumed and formed in a chemical reaction.