Thompson is the Best
AP Chem Rules!
100
What is the equilibrium expression for this reaction? P4(s) + 5 O2(g) ↔ P4O10(s)
Kc = [P4O10] / [P4] [O2] 5
100
Xenon tetrafluoride, XeF4, can be prepared by heating Xe and F2 together according to this equation. What is the equilibrium expression for this reaction?
Xe(g) + 2F2(g) ↔ XeF4(g)
K = [XeF4] / ( [Xe] [F2] 2 )
200
N2(g) + 3 H2(g) --> 2 NH3(g)
At equilibrium: [N2] = 1.50 M [H2] = 2.00 M [NH3]= 0.01 M
Calculate the value of Kc and state whether each equilibrium is product-favored, reactant-favored, or fairly even.
Kc = 8.33 x 10-6 and it is reactants-favored
200
Write the equilibrium expression for the following reaction: Ni(s) + 4CO(g) --> Ni(CO)4(g)
Kp = (PNi(CO)4) / (PCO)4
300
Write the Kc expression for 2 SO2(g) + O2(g) --> 2 SO3(g) Calculate the value of Kc: 4.36 At equilibrium: [SO2] = 1.50 M [O2] = 1.25 M [SO3]= 3.50 M
Kc = [SO3]2 / [SO2]2 [O2] and 4.36
300
2C(g) <--> A(g) + B(g) Kp = 0.00034
When 50 atm of C(g) is added to an empty, rigid container and allowed to reach equilibrium, the partial pressure of A(g) is approximately 5.6 atm. If the initial pressure of C(g) is decreased to 25 atm and the process is repeated at the same temperature, what is the correct prediction for the equilibrium partial pressure of A(g) and why?
PA ~ 2.8 atm because it is directly proportional to the pressure of C(g)
400
The particle diagram above shows the changes that take place between two particles when placed in a rigid container at a constant temperature. Describe if/when the system reached equilibrium and how did you know.
It reached equilibrium between t=2 and t=3 because the amounts of each species remained constant after that point.
400
Consider an equilibrium that occurs in two steps: H2S(aq) --> H+ (aq) + HS- (aq)
HS- (aq) --> H+ (aq) + S2- (aq)
a) Write the overall reaction.
b) How do the Kc’s for the two steps (Kc1 & Kc2) relate to the Kc of the overall reaction (Kc)?
H2S(aq) --> 2H+(aq) + S2-(aq)
Kc = Kc1 x Kc2
500
Calculate the value of Kc for the reaction: 2 N2O(g) + 3 O2(g) 
2 N2O4(g), using the following information.
1.1 x 106
500
Write the equilibrium expression for the equation below and determine the pressure of CO if at equilibrium (PO2) = 1.6 x 10-3 atm, (PCO2) = 3.2 x 10-2 atm, and Kp = 1.02 x 105
2 CO(g) + O2(g) ↔ 2CO2(g)
(PCO) = 2.5 x 10-3 atm