Lecture 19- Equilibrium 2

Question 1

The reaction quotient

Answer 1

• at a specific moment in time as opposed to equilibrium as it tries to go to equilibrium
• Kp/Kc is specific to a specific temperature
• Used to determine if the reaction is at equilibrium
• If Q=Kc then it is
• If Q>Kc, the system has too many products and the reaction will proceed to the left until equilibrium is reched

Question 2

What Q tells us

Answer 2

• Q>Keq then the reaction will proceed to the left, it will continue to increase the concentration of reactants until equilibrium is established
• Q

Question 3

Le Chatelier’s Principle

Answer 3

• When a system at equilibrium is subjected to a stress, the equilibrium will shift in order to reduce that stress
• The only three stresses are changes in pressure, concentrations, and temperature

Question 4

Stress from Increasing pressure

Answer 4

• If the pressure on a system at equilibrium is increased, Q changes and the equilibrium will shift toward the side with fewer moles of gas to reduce that stress
• This changes the equilibrium concentrations, but it does not change the equilibrium constant (Keq)

Question 5

Stress from decreasing pressure

Answer 5

• If the pressure on a system at equilibrium is decreased, Q changes and the equilibrium will shift toward the side with more moles of gas to reduce that stress
• This changes the equilibrium concentrations, but it does not change the Equilibrium constant (Keq)

Question 6

Stress from increasing concentrations

Answer 6

• If the concentration of one of the species is an equilibrium system is increased, Q changes and the equilibrium will shift in the direction that will reduce the concentration of that species
• This changes the equilibrium concentrations, but it does not change the Equilibrium constant (Keq)

Question 7

Stress of decreasing concentrations

Answer 7

• If the concentration of one of the species in an equilibrium system is decreased, Q changes and the equilibrium will shift in the direction that will increase the concentration of that species
• This changes the equilibrium concentrations, but it does not change the Equilibrium constant (Keq)

Question 8

Stress from Dilution

Answer 8

• If solvent is added to a system at equilibrium, Q changes and the equilibrium will shift toward the side with more particles to reduce that stress
• This changes the equilibrium concentrations, but it does not change the Equilibrium constant (Keq)

Question 9

Stress from changes in temperature

Answer 9

• This is the only stress that changes the equilibrium constant (Keq)
• When heat is added:
• Exothermic favors reactants
• Endothermic favors products

Question 10

Reciprocal rule

Answer 10

Kcii = 1/Kci

- for when reaction is reversed

Question 11

Multiple Equilibria Rule

Answer 11

Kci X Kciii = Kciv

- for when you have 2 of them to work with