Chemical Equilibrium and Reaction Rates

Flashcards covering key vocabulary and concepts related to chemical kinetics and equilibrium.

Rate of Reaction

The speed at which reactants are chemically converted into products.

Collision Theory

Describes chemical reactions in terms of reacting particles (atoms, ions or molecules), emphasizing the need for collisions with correct orientation and sufficient energy.

Energy Profile Diagram

Shows the changes in potential energy of the substances involved in a chemical reaction, illustrating activation energy, enthalpy change, and energy levels of reactants and products.

Nature of Reactants

The inherent properties of reactants that affect reaction rate, with simpler reactions (less bond breaking/forming) being faster than complex ones.

Concentration (Reaction Rate Factor)

Increasing reactant concentrations increases reaction rate due to more frequent collisions with sufficient energy and correct orientation.

Pressure/Volume (Reaction Rate Factor)

Increasing pressure (or decreasing volume) increases reaction rate by increasing the frequency of collisions between particles.

State of Subdivision of Reactants

Refers to the overall surface area of reactants; increasing it increases the reaction rate by exposing more reactant particles for collisions.

Agitation/Stirring

Increases reaction rate by creating movement in a fluid, exposing more reacting particles for collisions and providing them with more kinetic energy.

Temperature (Reaction Rate Factor)

Increasing temperature increases reaction rate by causing particles to vibrate and move faster, leading to more frequent and energetic collisions.

Catalyst

A substance that alters the rate of a chemical reaction by providing an alternate reaction pathway with a lower activation energy.

Chemical System

The environment in which a chemical reaction occurs; can be open (matter and energy exchange) or closed (energy exchange only).

Open Chemical System

A system where matter and energy can be exchanged between the system and its surroundings.

Closed Chemical System

A system where energy can be exchanged with the surroundings, but matter is contained within the system.

Chemical Equilibrium

The state where the rate of the forward reaction equals the rate of the reverse reaction in a reversible reaction, resulting in constant concentrations of reactants and products.

Irreversible Reaction

A reaction that proceeds in one direction only, represented by a single arrow (→).

Reversible Reaction

A reaction that can proceed in both forward and reverse directions, represented by two half arrows (⇌).

Dynamic Equilibrium

The state in a reversible reaction where the forward and reverse reactions continue to occur at equal rates, resulting in no net change in concentrations.

Phase Equilibrium

A physical process where equilibrium occurs between two states of matter, such as in a sealed container of a liquid where evaporation and condensation rates are equal.

Solution Equilibrium

A physical process where equilibrium occurs in a solution, with the rate of dissolving equal to the rate of recrystallization.

Equilibrium Constant (Kc)

A numerical value that compares the concentration of reactants to products at equilibrium, providing insight into the extent of a reaction.

Equilibrium Law Expression

A mathematical expression representing the ratio of products to reactants at equilibrium, with species in solid or liquid states excluded.

Equilibrium Position

Indicates whether the forward or reverse reaction is favored at equilibrium, based on the equilibrium constant or reaction conditions.

Yield

The amount of substance produced in a chemical reaction, indicating the effectiveness of the reaction.

Reaction Quotient (Q)

A measurement of the relative amounts of products and reactants present in a reaction mixture at a specific point in time.

Exothermic Reaction

A reaction that releases energy into the surroundings and has a negative change in enthalpy.

Endothermic Reaction

A reaction that absorbs energy from the surroundings and has a positive change in enthalpy.