Transcript
Page 1: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

“Equilibrium”“Equilibrium”

What does it mean? What word does it look like?

What does it mean? What word does it look like?

Page 2: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

Aim: How can we look at systems at equilibrium?

Aim: How can we look at systems at equilibrium?

Equilibrium: a state of balance

Dynamic Equilibrium: when overall rates of forward and reverse reactions are equal

This is a Reversible Equilibrium and is indicated by a double arrow

Equilibrium: a state of balance

Dynamic Equilibrium: when overall rates of forward and reverse reactions are equal

This is a Reversible Equilibrium and is indicated by a double arrow

Page 3: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

Physical EquilibriumPhysical Equilibrium

Physical Equilibrium is balance in physical processes

Phase equilibrium: equilibrium between phases

Physical Equilibrium is balance in physical processes

Phase equilibrium: equilibrium between phases

Page 4: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

Solution EquilibriumSolution Equilibrium

Solution Equilibrium: dissolving & crystallization happening at equal rate

Solution Equilibrium: dissolving & crystallization happening at equal rate

liquid-gasliquid-solid

Page 5: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

Chemical EquilibriumChemical Equilibrium

CH4 (g) + H2O (g) 3 H2 (g) + CO (g) CH4 (g) + H2O (g) 3 H2 (g) + CO (g)

Page 6: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

Chemical EquilibriumChemical Equilibrium

CH4 (g) + H2O (g) 3 H2 (g) + CO (g) CH4 (g) + H2O (g) 3 H2 (g) + CO (g)

Page 7: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

HomeworkHomework

Finish equilibrium review pages Finish equilibrium review pages

Page 8: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

Remember: Equilibrium is StabilityRemember: Equilibrium is Stability

CH4 + H2O 3 H2 + CO

Fwd rxn rate = Rev Rxn rate Using up reactants to make products

CH4 + H2O 3 H2 + CO

Fwd rxn rate = Rev Rxn rate Using up reactants to make products

Page 9: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

How will a closed system react when a stress if applied?

How will a closed system react when a stress if applied?

equilibrium

stress

new equilibrium

Page 10: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

Le Chatelier’s PrincipleLe Chatelier’s Principle

Closed systems will adjust to balance stresses Concentration, temperature, pressure

Shifts are increased reaction rates in either Fwd (right→) or Rev (left←) directions

Closed systems will adjust to balance stresses Concentration, temperature, pressure

Shifts are increased reaction rates in either Fwd (right→) or Rev (left←) directions

Page 11: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?
Page 12: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?
Page 13: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

ConcentrationConcentration

Pen/pencil trick, pointing towards shift

A + B C

Add-Away, Take-Towards

Pen/pencil trick, pointing towards shift

A + B C

Add-Away, Take-Towards

Page 14: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?
Page 15: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?
Page 16: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

https://www.youtube.com/watch?v=7zuUV455zFs

https://www.youtube.com/watch?v=7zuUV455zFs

Page 17: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

ConcentrationConcentration Add-Away Add-Away

Page 18: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

ConcentrationConcentration Take-Towards Take-Towards

Page 19: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

Le Chatelier’s Principle:Temperature

Le Chatelier’s Principle:Temperature

Treat “heat/energy” like any other reactant

Adding heat favors reaction Removing heat favors reaction

Treat “heat/energy” like any other reactant

Adding heat favors reaction Removing heat favors reaction

Page 20: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

N2 + 3 H2 2 NH3 + 22 kJN2 + 3 H2 2 NH3 + 22 kJ

Page 21: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

12.6 kJ + H2 + I2 2 HI12.6 kJ + H2 + I2 2 HI

Page 22: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

Do Now: Answer the following questionsDo Now: Answer the following questions

1. What is Le Chatelier’s Principle? 2. Label the forward and reverse reactions as

endothermic or exothermic:

CO (g) + 3 H2 CH4 (g) + H2O (g) + heat

3. In which direction will equilibrium shift if the temperature is increased?

4. In which direction will equilibrium shift if the temperature is decreased?

1. What is Le Chatelier’s Principle? 2. Label the forward and reverse reactions as

endothermic or exothermic:

CO (g) + 3 H2 CH4 (g) + H2O (g) + heat

3. In which direction will equilibrium shift if the temperature is increased?

4. In which direction will equilibrium shift if the temperature is decreased?

Page 23: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

PressurePressure

Only for gases; count # of molecules on each side

If # is equal, pressure has no effect

pressure shifts towards fewer molecules

pressure shifts towards more molecules

Only for gases; count # of molecules on each side

If # is equal, pressure has no effect

pressure shifts towards fewer molecules

pressure shifts towards more molecules

Page 24: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

Pressure ExamplePressure Example

4 NH (g) + 5 O2 (g) 4 NO (g) + 6 H2O (g)

= gas molecules = gas molecules

Increase pressure: shift (more to less) 9 10

Decrease pressure: shift (less to more) 9 10

4 NH (g) + 5 O2 (g) 4 NO (g) + 6 H2O (g)

= gas molecules = gas molecules

Increase pressure: shift (more to less) 9 10

Decrease pressure: shift (less to more) 9 10

Page 25: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

N2 + 3 H2 2 NH3N2 + 3 H2 2 NH3

Equilibriumshift [N2] [H2] [NH3]

# molecules:

Increased pressure shifts towards fewer moleculesDecreased pressure shifts towards more molecules

Page 26: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

H2 + I2 2 HIH2 + I2 2 HI

Equilibriumshift [H2] [I2] [HI]

# molecules:

Increased pressure shifts towards fewer moleculesDecreased pressure shifts towards more molecules

Page 27: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

Conclusion QuestionsConclusion Questions

1. How does a system at equilibrium respond to a stress? List the factors that can be stresses on an equilibrium system.

1. How does a system at equilibrium respond to a stress? List the factors that can be stresses on an equilibrium system.

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Conclusion QuestionsConclusion Questions

2. Given the reaction at equilibrium:

N2 (g) + 3 H2 (g) 2 NH2 (g) + heat

Which stress would cause the equilibrium to shift to the left? (a) Increasing the temperature (b) Adding N2 (g) to the system (c) Adding H2 (g) to the system

2. Given the reaction at equilibrium:

N2 (g) + 3 H2 (g) 2 NH2 (g) + heat

Which stress would cause the equilibrium to shift to the left? (a) Increasing the temperature (b) Adding N2 (g) to the system (c) Adding H2 (g) to the system

Page 29: “Equilibrium”  What does it mean?  What word does it look like?  What does it mean?  What word does it look like?

Conclusion QuestionsConclusion Questions

2. Given the reaction at equilibrium:

N2 (g) + O2 (g) 2 NO (g)

If the concentration of N2 (g) is increased, the concentration of O2 (g) will (a) Decrease (b) Remain the same (c) Increase

2. Given the reaction at equilibrium:

N2 (g) + O2 (g) 2 NO (g)

If the concentration of N2 (g) is increased, the concentration of O2 (g) will (a) Decrease (b) Remain the same (c) Increase


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