WARM UP
How would I balance a scale like this
when it is uneven like the picture?
HOMEWORK
• Complete worksheet for Tuesday.
• Pre-lab and post-lab due Monday!
AGENDA
1. Warm Up, Prayer, Homework
2. Le Chatelier’s Principle Notes
3. Whiteboards
4. Worksheet
5. Test Review
CHEMICAL REACTI0NS
• When reactants are making products, we call
this the forward reaction (reaction moving
right)
Forward Reaction
• When products are breaking down into
reactants, we call this the reverse reaction
(reaction moving left)
Reverse Reaction
EQUILIBRIUM
• When a reaction is at equilibrium, it is shown in two
different ways. Instead of a single arrow (
) after
the reactants, you might see:
_________________ or ______________.
THE EQUILIBRIUM STATE
• Equilibrium is the state where the rate of the
forward reaction is equal to the rate of the
reverse reaction.
• At these conditions, concentrations of all
reactants and products remain constant with
time once equilibrium has been established at
constant temperature.
THE EQUILIBRIUM STATE
LE CHATELIER
What are the 4 factors that affect equilibrium?
1.
2.
3.
4.
Heat (in joules)
Pressure (of a gas)
Concentration of Reactant
Concentration of Product
EQUILIBRIUM
• Le Chatelier's principle can be used to
predict the effect of a change in conditions
on a chemical equilibrium.
LE CHATELIER
Factors Affecting Equilibrium Reactions
Type of variable
Increasing will have an
effect by..
Heat (Joules, J or SHIFT AWAY
kilojoules, kJ)
SHIFT AWAY
Reactant
(concentration of
reactants):
SHIFT AWAY
Product
(concentration of
products):
Pressure (of a gas) SHIFT TOWARDS
less moles of gas!
Decreasing will have an
effect by..
SHIFT TOWARDS
SHIFT TOWARDS
SHIFT TOWARDS
SHIFT TOWARDS
more moles of gas!
LE CHATELIER
Factors Affecting Equilibrium Reactions
Type of variable
Increasing will have an
effect by..
Heat (Joules, J or SHIFT AWAY
kilojoules, kJ)
SHIFT AWAY
Reactant
(concentration of
reactants):
SHIFT AWAY
Product
(concentration of
products):
Pressure (of a gas) SHIFT TOWARDS
less moles of gas!
Decreasing will have an
effect by..
SHIFT TOWARDS
SHIFT TOWARDS
SHIFT TOWARDS
SHIFT TOWARDS
more moles of gas!
LE CHATELIER
Factors Affecting Equilibrium Reactions
Type of variable
Increasing will have an
effect by..
Heat (Joules, J or SHIFT AWAY
kilojoules, kJ)
SHIFT AWAY
Reactant
(concentration of
reactants):
SHIFT AWAY
Product
(concentration of
products):
Pressure (of a gas) SHIFT TOWARDS
less moles of gas!
Decreasing will have an
effect by..
SHIFT TOWARDS
SHIFT TOWARDS
SHIFT TOWARDS
SHIFT TOWARDS
more moles of gas!
LE CHATELIER
Factors Affecting Equilibrium Reactions
Type of variable
Increasing will have an
effect by..
Heat (Joules, J or SHIFT AWAY
kilojoules, kJ)
SHIFT AWAY
Reactant
(concentration of
reactants):
SHIFT AWAY
Product
(concentration of
products):
Pressure (of a gas) SHIFT TOWARDS
less moles of gas!
Decreasing will have an
effect by..
SHIFT TOWARDS
SHIFT TOWARDS
SHIFT TOWARDS
SHIFT TOWARDS
more moles of gas!
LE CHATELIER
Factors Affecting Equilibrium Reactions
Type of variable
Increasing will have an
effect by..
Heat (Joules, J or SHIFT AWAY
kilojoules, kJ)
SHIFT AWAY
Reactant
(concentration of
reactants):
SHIFT AWAY
Product
(concentration of
products):
Pressure (of a gas) SHIFT TOWARDS
less moles of gas!
Decreasing will have an
effect by..
SHIFT TOWARDS
SHIFT TOWARDS
SHIFT TOWARDS
SHIFT TOWARDS
more moles of gas!
LE CHATELIER’S PRINCIPLE
Example:
2 C2 H6 (l) + 5 O2 (g) + heat  4 CO2 (g) + 6 H2 O (g)
Which way would the reaction shift if H2O is increased?
What will happen to the products and reactants?
More
Less
LE CHATELIER’S PRINCIPLE
Example:
2 C2 H6 (l) + 5 O2 (g) + heat  4 CO2 (g) + 6 H2 O (g)
What direction will the reaction shift if temperature/heat
was decreased?
What will happen to the products and reactants?
More
Less
LE CHATELIER’S PRINCIPLE
Example:
2 C2 H6 (l) + 5 O2 (g) + heat  4 CO2 (g) + 6 H2 O (g)
What direction will the reaction shift with increased
pressure?
What will happen to the products and reactants?
More
Less
EXIT SLIP
During the exit slip:
Silently working
Notes away
When finished, flip over your exit slip and
wait silently in your seat for your peers to
finish.