Introduction to Equilibrium
Introduced| English |
|---|
| equilibrium/ˌiːkwɪˈlɪbrɪəm/ |
A busy standstill
- Some reactions never fully finish -- they reach a balance.
- Reactants and products settle at steady amounts.
- But underneath, the reaction is still running both ways.
- It is a standstill built from constant motion.
Both ways at once
- A reversible reaction runs forward and backward at the same time.
- At equilibrium 平衡, the two rates become equal.
- It is dynamic: both directions keep going, just in balance.
At equilibrium, the forward and reverse reaction rates are...
Equal rates keep the concentrations constant.
Steady, not stopped
- At equilibrium, the concentrations stay constant.
- They are not zero, and not necessarily equal to each other.
- Products form as fast as they break back down.
At equilibrium, the concentrations of reactants and products are...
They stop changing but are not necessarily equal to each other.
At equilibrium the concentrations hold ____ over time.
Equal opposing rates keep concentrations steady.
At equilibrium the reactant concentrations are zero.
Both reactants and products remain present at steady amounts.
How to spot equilibrium
- The forward rate equals the reverse rate.
- The concentrations hold steady over time.
- The reaction has not stopped; it is balanced.
Reaching dynamic equilibrium
Watch a reversible reaction settle into equilibrium.
At equilibrium, both the forward and reverse reactions have stopped.
Equilibrium is dynamic -- both keep running at equal rates.
Reaching equilibrium means the reaction has completely finished.
The reaction continues in both directions, just in balance.
Why do the amounts stop changing at equilibrium?
- The forward and reverse reactions run at the same speed.
- Each product made is matched by one breaking down.
Equilibrium is dynamic, not static -- both reactions still happen, just at equal rates. Concentrations are constant but usually not equal to each other. And "equilibrium" does not mean the reaction stopped; it means the two directions balance.
At equilibrium a reversible reaction's forward and reverse rates are equal, so the concentrations hold steady -- constant but not zero and not necessarily equal. It is dynamic: both directions keep running in perfect balance, not stopped.