Chemical Equilibrium and Equilibrium Constant Quiz

Study Notes

Chemical Equilibrium

Chemical equilibrium is a state in which a chemical reaction between reactants reaches a dynamic balance, meaning that the rates at which reactants are forming products are equal to the rates at which products are decomposing back into reactants. In this state, the concentrations of reactants and products do not change with time, and the reaction is said to be at equilibrium.

Equilibrium Constant

The equilibrium constant is a measure of the equilibrium position in a reaction, representing the ratio of the product concentrations to the reactant concentrations at equilibrium. It is a dimensionless quantity and is typically calculated from the concentrations of the reactants and products at equilibrium. The equilibrium constant for a reaction is also known as the "thermodynamic driving force".

Le Chatelier's Principle

Le Chatelier's Principle is a concept in chemistry that states that when a system at chemical equilibrium is subjected to a change in concentration, pressure, or temperature, the system will respond by adjusting its position so as to minimize the effect of the change. This principle is based on the law of mass action, which states that the rate of a reaction is proportional to the product of the concentrations of the reactants.

Reaction Quotient

The reaction quotient is a dimensionless quantity that represents the ratio of the product concentrations to the reactant concentrations at any point during a reaction. It is defined as the ratio of the product concentrations raised to their stoichiometric coefficients to the reactant concentrations raised to their stoichiometric coefficients. The reaction quotient is used to determine the direction of a reaction and can be used to calculate the equilibrium constant.

Equilibrium Position

The equilibrium position is the state of a reaction where the concentrations of the reactants and products are such that the reaction occurs at a net zero rate. In other words, the forward reaction and the reverse reaction are occurring at equal rates, and the concentrations of the reactants and products do not change.

Factors Affecting Equilibrium

Several factors can affect the equilibrium position of a reaction, including changes in temperature, pressure, and concentration of reactants and products. An increase in the concentration of a reactant will shift the equilibrium position in the direction that reduces the concentration of that reactant, while a decrease in the concentration of a reactant will shift the equilibrium position in the opposite direction. Similarly, an increase in the concentration of a product will shift the equilibrium position in the direction that reduces the concentration of that product, while a decrease in the concentration of a product will shift the equilibrium position in the opposite direction.