AP Equilibrium Concepts Flashcards
When is equilibrium reached?
when the rate of reactants becoming products equals the rate of products becoming reactants
How to write the equilibrium expression
write K = concentration of the products raised to their coefficients divided by the reactants raised to their coefficients (in the reaction equation)
Are solids and liquids included in the equilibrium expression?
NO, never
What are Kc, Kp, Ksp, Ka, and Kb?
Kc- constant for concentrations Kp- constant for pressures Ksp- constant for sparingly soluble salts Ka- constant for acids Kb- constant for bases
What is the difference between Q and K?
K is the proportion of (products/reactants) at equilibrium
Q is the proportion of (products/reactants) at a specific time
If Q > K, the reaction shifts
left (reactants formed, products used)
If Q
right (products formed, reactants used)
If Q = K, then
the reaction is at equilibrium
If K > 1, reaction shifts
right (more products than reactants)
If K
left (more reactants than products)
What does ICE stand for?
Initial
Concentration Change
Equilibrium
How to use ICE
1) write ICE in a column
2) write the reaction equation
3) write in the given initial concentrations (if problem doesn’t say initial concentration for something assume it’s 0)
4) subtract x from products and add x from reactants (remember to make the equation’s coefficient the coefficient of x)
5) add/subrtact down to find equilibrium values
6) write the equilibrium expression with the variable
7) solve for x
How to avoid the quadratic when using ICE
1) follow steps 1-6 for ICE
2) cross out x so you can avoid using the quadratic formula and solve for x easily
3) go back and check: divide x by the initial concentrations and see if it is less that 5% of them
4) if yes: you avoided the quad formula
if no: you have to use the quad formula
If the reaction shifts right, ___ reaction moves faster than ___ reaction
forward; reverse
If the reaction shifts left, ___ reaction moves faster than ___ reaction
reverse; forward
