Chemical Equilibrium, Reaction Quotients, and ICE Tables

Vocabulary flashcards covering chemical equilibrium, reaction quotients ($$Q_c$$ and $$Q_p$$), equilibrium criteria, ICE table setup, and mathematical methods for solving equilibrium concentrations.

Equilibrium Constant ($K_c$)

An expression representing product concentrations divided by reactant concentrations, which applies exclusively when a reaction system is at equilibrium.

Reaction Quotient ($Q_c$)

An expression representing product concentrations divided by reactant concentrations calculated at any point in time, whether the reaction system is at equilibrium or not.

Equilibrium Condition ($Q_c = K_c$)

The condition where the reaction quotient equals the equilibrium constant, signifying that the chemical system is at equilibrium.

Forward Shift Condition ($Q_c < K_c$)

The condition occurring when the concentration of products is lower than at equilibrium, causing the reaction to proceed toward the right in the forward direction to form more products.

Backward Shift Condition ($Q_c > K_c$)

The condition occurring when product concentration is higher than at equilibrium, causing the equilibrium to shift left toward the backward direction to form more reactants.

Pressure-Based Equilibrium Constant ($K_p$)

An equilibrium constant derived from the partial pressures of gases, which is treated as unitless.

Reaction Quotient for Pressure ($Q_p$)

An expression determined using the partial pressures of products divided by reactants at any point in time to compare against $K_p$.

Atmosphere ($\text{atm}$)

The standard unit of measurement for partial pressures when evaluating gas-phase equilibrium constants and reaction quotients.

ICE Table

A systematic tabular method detailing Initial concentration, Change, and Equilibrium concentration, used to solve for unknown concentrations or equilibrium constants.

Law of Mass Action

The chemical principle dictating that the balanced reaction's stoichiometric coefficients define the powers and stoichiometric factors in equilibrium and change expressions.

Quadratic Equation in Equilibrium ($ax^2 + bx + c = 0$)

A second-degree polynomial equation used to solve for the concentration change $x$, where only the solution resulting in a positive concentration is physically valid.