Name_________________________________________________ Period____ Date_________________
Chemical Equilibrium
Guided Notes
Chemical equilibrium occurs when a ___________________________________________________________ proceed
at the same rate.
Reversible Reaction: A chemical reaction in which the products can react to ___________________________________.
Forward: H2 + I2  2HI
Reverse: 2HI  H2 + I2
Arrows going both directions () indicates equilibrium in a
chemical reaction.
A chemical equilibrium occurs and _______________________
occurs in the actual amounts of the components of the
system.
Video Guiding Questions:
What challenges does Wallenda face while trying to
stay on the tightrope?
What is he doing to keep his balance?
How does represent an equilibrium state?
LeChatelier’s Principle
When a system at equilibrium is placed under stress, the system will undergo a change in
such a way as to relieve that stress.
Le Chatelier Translated:
When you take something away from a system at equilibrium, the system
______________ in such a way as to
________________________________________________.
When you add something to a system at equilibrium, the system ______________ in such a way as to
______________________________________________________.
A System at Equilibrium:
Once equilibrium is achieved, the ________________ of each
reactant and product remains _________________.
3 Factors that influence the position of an equilibrium
1.
Adding more reactant produces more product and removing the product as it
forms will produce more product.
2.
Increasing the temperature causes the equilibrium position to shift in the
direction that absorbs heat.
3.
Changes in pressure will only effect gaseous equilibria. Increasing the pressure
will usually favor the direction that has fewer molecules.
Conditions for Equilibrium:
1. The system must be __________________, meaning no substances can enter or leave the system.
2. Equilibrium is a __________________ _____________. Even though we don’t necessarily see the reactions,
both forward and reverse are taking place.
3. The rates of the forward and reverse reactions must be _____________.
4. The amount of reactants and products do not have to be equal. However, after equilibrium is attained, the
amounts of reactants and products will be ______________.
LeChatlier Example #1
A closed container of ice and water at equilibrium. The ____________________________________________________.
Ice + Energy  Water
The equilibrium of the system shifts to the ________________ to use up the added energy.
LeChatlier Example #2
A closed container of N2O4 and NO2 at equilibrium. ________________________ to the container.
N2O4 (g) + Energy  2 NO2 (g)
The equilibrium of the system shifts to the _____________ to use up the added NO2.
LeChatlier Example #3
A closed container of water and its vapor at equilibrium. ________________________________ from the system.
Water + Energy  vapor
The equilibrium of the system shifts to the ________________ to replace the vapor.
LeChatlier Example #4
A closed container of N2O4 and NO2 at equilibrium. The ________________________________.
N2O4 (g) + Energy  2 NO2 (g)
The equilibrium of the system shifts to the ______________ to lower the pressure, because there are fewer moles of gas
on that side of the equation.