Chemical Equilibrium Flashcards

Flashcards to review key vocabulary related to chemical equilibrium, including static vs dynamic equilibrium, types of equilibrium states, reversible reactions, and equilibrium expressions.

Chemical Equilibrium

The state in which the rate of the forward reaction is the same as the rate of the reverse reaction.

Static Equilibrium

Exists when a given system is not changing in motion—when balanced forces act on an object.

Dynamic Equilibrium

Exists when opposing states occur at the same rate and no overall change occurs; the states become balanced.

Book resting on a table (Static Equilibrium)

Gravitational force pulling the book down is balanced by the normal force exerted by the table upwards, resulting in zero net force and no movement.

A person standing still (Static Equilibrium)

The gravitational force pulling the person down is balanced by the normal force exerted by the floor upwards, keeping them stationary.

A parked car (Static Equilibrium)

The weight of the car is evenly distributed among the tires, and the ground provides an equal and opposite force, preventing the car from moving.

A balanced seesaw (Static Equilibrium)

When the forces (weight) on both sides of the fulcrum are equal, the seesaw remains horizontal and doesn't rotate.

A hanging picture (Static Equilibrium)

The tension in the wire holding the picture balances the gravitational force, keeping the picture in place.

Escalator Example (Dynamic Equilibrium)

A girl is running up an escalator that is moving down. If her speed is equal to that of the escalator, her position will remain the same.

Saturated Solution (Dynamic Equilibrium)

The rate of dissolving is equal to the rate of recrystallization.

Evaporation in a closed system (Dynamic Equilibrium)

Vaporization and liquefaction are in equilibrium.

Percentage of oxygen and carbon dioxide in the air (Dynamic Equilibrium)

Gases are produced as much as they are used up.

Dynamic Equilibrium (Nature)

Reversible in nature.

Static Equilibrium (Nature)

Irreversible in nature.

Dynamic Equilibrium (Reactions)

Reactants and the products are still participating in chemical reactions.

Static Equilibrium (Reactions)

There is no further chemical reaction in the system.

Dynamic Equilibrium (Rates)

The forward and the backward reaction rates are equal.

Static Equilibrium (Rates)

The forward and backward reaction rates are zero.

Thermal Equilibrium

Occurs when heat is transferred from a higher temperature to a lower temperature until balance in heat is achieved.

Phase Equilibrium

Occurs when the transfer of matter or heat energy from one phase to another is in a state of balance with the rate of transfer in the reverse reaction.

Mechanical Equilibrium

A state in which there is no change in pressure throughout the system concerning time.

Chemical Equilibrium (Conditions)

The amounts of the reactants and products are observed to be constant after some time, and the rate of the product formed from the reactant is equal to the rate of the reverse reaction.

Reversible Reactions

A reaction that may proceed not only from a single direction but from both ends.

Complete Reaction

A reaction wherein no reactants remain in the mixture and the reverse reaction does not occur.

Equilibrium System Condition

The rate of the forward reaction should be equal to the rate of the reverse reaction.

Cato Maximilian Guldberg and Peter Waage’s work

Deals with the calculation of reaction quotients at equilibrium; known as the law of mass action.

Equilibrium expressions

Equations called equilibrium constant expressions.

Keq

Equilibrium constant

Heterogeneous reactions

Equilibrium reactions involving components in more than one phase

Reaction Quotient

Numerical value of the reaction quotient which change as the reaction progresses, until the system is at equilibrium.