Chemical Equilibrium Fundamentals

A mathematical expression linking the equilibrium constant to the concentrations of reactants and products at equilibrium, taking stoichiometry into account.

A constant value describing the ratio of product concentrations to reactant concentrations at equilibrium.

Solids and liquids are ignored in equilibrium expressions because their concentrations remain constant during the reaction.

A reaction where all reactants and products are in the same physical state (e.g., all gases).

A reaction where reactants and products are in different physical states (e.g., gas, solid, liquid).

An equilibrium constant expressed in terms of partial pressures of gases.

Equilibrium expression for gaseous reactions using partial pressures instead of concentrations.

The equilibrium constant (K) only changes if the temperature of the reaction changes.

The total entropy change of a reaction (∆S) is related to the equilibrium constant (K) by a specific equation. This equation highlights the relationship between the spontaneity of a reaction and its equilibrium position.

We can rearrange the equation relating total entropy change and the equilibrium constant to directly calculate the equilibrium constant (K) from the entropy change (∆S) of a reaction.

A very large value of the equilibrium constant (K) usually indicates that the equilibrium position lies heavily towards the product side of a reaction.

A small equilibrium constant (K) suggests that the equilibrium position favors the reactant side of a reaction. This means the reactants are more abundant at equilibrium.

There isn't a fixed rule to directly connect the magnitude of the equilibrium constant (K) to the exact position of equilibrium. However, K can usually give an idea of which side is favored.

The equilibrium constant for gaseous reactions can be expressed in terms of partial pressures (Kp), indicating the ratio of partial pressures of products to reactants at equilibrium.

The total entropy change (∆S) for a reaction represents the overall change in disorder or randomness of the system during the reaction. It includes both the entropy change for the system (products and reactants) and the surroundings.

A state in a reversible reaction where the forward and reverse reaction rates are equal, resulting in no net change in the concentrations of reactants and products over time.

Their concentrations remain constant during the reaction, as the amount of solid or liquid doesn't change significantly during the reaction process.

The value of Kc changes only if the temperature of the reaction changes. It is not affected by changes in pressure, volume, or concentration.

An equilibrium constant expressed in terms of the partial pressures of gases involved in the reaction at equilibrium, symbolized by Kp.

Kp and Kc are related by the equation: Kp = Kc(RT)^Δn, where R is the ideal gas constant, T is the temperature in Kelvin, and Δn is the difference in the number of moles of gaseous products and reactants.

A large value of Kc indicates that the equilibrium lies towards the products, meaning the reaction favors the formation of products at equilibrium.

A small value of Kc indicates that the equilibrium lies towards the reactants, meaning the reaction favors the formation of reactants at equilibrium.

Reversing a reaction means swapping the products and reactants, which results in the reciprocal value of the original Kc.

A method used to calculate equilibrium concentrations of reactants and products in a reaction. It tracks the initial moles, change in moles, and ending (equilibrium) moles of each substance.

The equilibrium constant (K) has no units if all reactants and products are in the same phase (homogeneous). If different phases are involved (heterogeneous), the units depend on the specific reaction.

The final answer for K should be rounded to the same number of significant figures as the least precise value used in the calculation.

A chemical reaction where a molecule is broken down by the addition of a water molecule.

The ratio of the coefficients in a balanced chemical equation, representing the relative number of moles of reactants and products involved in a reaction.

The method used to calculate the equilibrium constant (Kc) based on the concentrations of reactants and products at equilibrium.

Calculating the concentration of a substance using the number of moles and the volume of the mixture.

Each term within the square brackets in the Kc expression represents the concentration of a reactant or product in mol/dm3.

The equilibrium constant (Kc) is calculated by dividing the product of the concentrations of products (raised to their stoichiometric coefficients) by the product of the concentrations of reactants (also raised to their stoichiometric coefficients).

The stoichiometric coefficients of the balanced chemical equation directly affect the power to which each concentration term is raised in the Kc expression.

The concentrations of pure solids and liquids are considered constant and are not included in the Kc expression.

The value of Kc is only affected by changes in temperature, not by changes in pressure, volume, or concentration.

A large Kc value indicates that the equilibrium position lies heavily towards the product side of the reaction, meaning the products are favored.