Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Chemical Equilibrium: Reaction Mechanisms

In course

CH-310: Dynamics and kinetics

The course covers the principles of chemical kinetics, including differential rate laws, derivation of exact and approximate integral rate laws for common elementary and composite reactions, fundamentals of collision and transition state theories, and appl ...

Description

This lecture covers the concept of chemical equilibrium focusing on reaction mechanisms. It discusses how to determine equilibrium concentrations of chemical species based on initial conditions and rate constants. The lecture also explores consecutive reactions with reversible steps and the derivation of expressions for concentrations of reactants and products. Additionally, it includes the analysis of concentration sketches for different scenarios and the interpretation of system behavior. Emphasis is placed on understanding the time dependence of concentrations and identifying similar behaviors in complex reactions.

Instructor

Ulrich Lorenz

Official source

Related concepts (32)

Chemical equilibrium

In a chemical reaction, chemical equilibrium is the state in which both the reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the system. This state results when the forward reaction proceeds at the same rate as the reverse reaction. The reaction rates of the forward and backward reactions are generally not zero, but they are equal. Thus, there are no net changes in the concentrations of the reactants and products.

Equilibrium constant

The equilibrium constant of a chemical reaction is the value of its reaction quotient at chemical equilibrium, a state approached by a dynamic chemical system after sufficient time has elapsed at which its composition has no measurable tendency towards further change. For a given set of reaction conditions, the equilibrium constant is independent of the initial analytical concentrations of the reactant and product species in the mixture.

Rate equation

In chemistry, the rate law or rate equation for a chemical reaction is a mathematical equation that links the rate of forward reaction with the concentrations or pressures of the reactants and constant parameters (normally rate coefficients and partial reaction orders). For many reactions, the initial rate is given by a power law such as where [\mathrm{A}] and [\mathrm{B}] express the concentration of the species \mathrm{A} and \mathrm{B}, usually in moles per liter (molarity, M).

Reaction mechanism

In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical reaction occurs. A chemical mechanism is a theoretical conjecture that tries to describe in detail what takes place at each stage of an overall chemical reaction. The detailed steps of a reaction are not observable in most cases. The conjectured mechanism is chosen because it is thermodynamically feasible and has experimental support in isolated intermediates (see next section) or other quantitative and qualitative characteristics of the reaction.

Chemical reaction

A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur.

Related lectures (52)

Chemical Equilibrium: Principles and Applications

Explores chemical equilibrium principles, including Le Châtelier's Principle and equilibrium constants, and discusses the influence of temperature, pressure, and concentration on equilibrium shifts.

Second Law of Thermodynamics

Explores the Second Law of Thermodynamics, Gibbs Free Energy, equilibrium constants, and Le Châtelier's Principle.

Chemical Equilibrium: Dissolution and Reaction Kinetics

Discusses dissolution, reaction kinetics, and chemical equilibrium with laws of reaction rates and equilibrium constants.

Chemical Equilibria and Reactivity

Delves into chemical equilibria, electrolysis, reaction kinetics, and chain reactions.

Chemical Reactions: Batch Reactor Analysis