Chemical Equilibrium

Chemical Equilibrium and Rates of Reactions

• At equilibrium, the rates of forward and reverse reactions are equal, and the concentrations of reactants and products are constant.
• The equilibrium constant (Keq) represents the unchanging concentrations of reactants and products at equilibrium, and it is calculated using the molar concentrations of all species in the reaction.
• ΔG at equilibrium is zero, indicating no net flow in either the forward or reverse direction, and neither process is favored.
• Le Châtelier’s Principle states that if an external stress is applied to a system at equilibrium, the system adjusts to partially offset the stress as it reaches a new equilibrium position.
• Changes in concentration, pressure, volume, and temperature can shift the equilibrium position according to Le Châtelier’s Principle.
• Adding a catalyst does not change the equilibrium constant (Keq) or shift the position of an equilibrium system, but it speeds up the reaction.
• The rate of a chemical reaction depends on the concentration of reacting species, reaction temperature, presence of catalysts, and the nature of the reactants.
• A catalyst promotes or increases the rate of a reaction without undergoing any permanent chemical change.
• Enzymes, which are biological catalysts, permit reactions to occur at conditions tolerable to the body and are very specific in their action, processing millions of molecules every second.
• Enzymes are classified based on the type of reaction they catalyze, such as oxidoreductase, transferase, hydrolase, lyase, isomerase, and ligase.
• Metabolism, the sum of all chemical reactions in a living organism, can be subdivided into two categories: catabolism (breaking down of complex molecules) and anabolism (building of complex molecules).
• The rate of a reaction is influenced by the concentration of reacting species, reaction temperature, presence of catalysts, and the nature of the reactants.