quiz 2 Flashcards
True or false: many reactions go to completion
False. Many reactions stop at an intermediate state where the system contains both reactants and products
What is chemical equilibrium
Concentrations of products and reactants remain constant with time
Are reactions at chemical equilibrium static on the microscopic level
NO. They are dynamic microscopically and static MACROscopically
Describe the microscopic change occurring in a reaction at equilibrium
Reaction continues to occur in both the forwards and reverse directions
Do the concentrations of reactants and products change in a reaction at equilibrium
No
Describe the relationship between the rate of the forward reaction and reverse reaction
The rate of the forward reaction and reverse reaction are equal
Where does the equilibrium lie when a reaction goes to completion
To the right
Where does the equilibrium lie when a reaction does not proceed much
To the left
How does the law of mass action work
Gives K the equilibrium constant
Concentrations of products / reactions
Each compound is raised to the exponent of their coefficient
When we reverse reaction what happens to K
K = 1/K
When we multiply the coefficients by a number what happens to K
Multiply by 1/2
K = K^(1/2)
When we add equations what happens to the Ks
A + B
K (of A) x K (of B) = K
When does Kp = Kc
When Δn = 0
State the formula for Kp
Kp = Kc (RT)^(Δn)
What is not included in calculating the equilibrium constant
Solids or liquids
What is the reaction quotient Q
Q is the law of mass action with INITIAL concentrations
When Q
Too much reactant, so shifts to right
When Q=K
At equilibrium
When Q>K
Too much product, so shifts to left
What does an ICE table stand for
I = initial C = change E = equilibrium
What is the 5% rule
When we have x^3, cubic function, must assume x in denominator is 0 and solve. THEN must check approximation and see if under 5%
What are the units for an ICE table
Moles, molarity or partial pressures
What is le Chateliers principle
If a change is imposed on a system at equilibrium, the position of equilibrium will shift in a direction which minimizes the change
According to le Chateliers principle what happens if a reactant or product is added
Shift to lower the concentration of it
According to le Chateliers principle what happens if a reactant or product is removed
Shift to increase concentration of it
Do solids or liquids affect le Chateliers principle
No
Describe what happens if pressure increases according to le Chateliers principle
Volume must decrease so shift to decrease moles
**no change if moles are the same on both sides
Describe what happens if pressure decreases according to le Chateliers principle
Volume must increase so shift to increase moles
How does heat work with le Chateliers principle
By treating heat as a reactant or product we can predict the shift of equilibrium
