Key Concepts and Summary
A reversible reaction is at equilibrium when the forward and reverse processes occur at equal rates. Chemical equilibria are dynamic processes characterized by constant amounts of reactant and product species.
The “double harpoon” arrow ($\rightleftharpoons $) is used to denote reactions that are equilibrium reactions (are proceeding or can proceed in both directions).Practice Problems: Chemical Equilibrium
What does it mean to describe a reaction as “reversible”?
Solution
The reaction can proceed in both the forward and reverse directions.
When writing an equation, how is a reversible reaction distinguished from a nonreversible reaction?
If a reaction is reversible, when can it be said to have reached equilibrium?
Solution
When a system has reached equilibrium, no further changes in the reactant and product concentrations occur; the forward and reverse reactions continue to proceed, but at equal rates.
Is a system at equilibrium if the rate constants of the forward and reverse reactions are equal?
If the concentrations of products and reactants are equal, is the system at equilibrium?
Solution
Not necessarily. A system at equilibrium is characterized by constant reactant and product concentrations, but the values of the reactant and product concentrations themselves need not be equal.
Glossary
- reversible reaction
- chemical reaction that can proceed in both the forward and reverse directions under given conditions
- equilibrium
- state of a reversible reaction in which the forward and reverse processes occur at equal rates equilibrium constant (K)