AP Chapter 14: Chemical Equilibrium & Ksp

1 AP Chapter 14: Chemical Equilibrium & Ksp Name_____ Warm-Ups (Show your work for credit) Date_____ 1. Date_____ 2. Answer: Answer: Date_____ 3. Date_____ 4. Answer: Answer: Date_____ 5. Date_____ 6. Answer: Answer: Date_____ 7.

2 Date_____ 8. Answer: Answer: AP Chapter 14: Chemical Equilibrium & Ksp 2 Warm-Ups (Show your work for credit) Date_____ 1. Date_____ 2. Answer: Answer: Date_____ 3. Date_____ 4. Answer: Answer: Date_____ 5.

3 Date_____ 6. Answer: Answer: Date_____ 7. Date_____ 8. Answer: Answer: AP Chapter 14: Chemical Equilibrium & Ksp 3 Warm-ups and problems will be collected before you take the test. Read Chapter 14: Chemical Equilibrium and Chapter : Solubility Product Answer the following problems in the space provided. For problems involving an equation, carry out the following steps: 1.

4 Write the equation. 2. Substitute numbers and units. 3. Show the final answer with units. There is no credit without showing work. Relationship between Kinetics and Equilibrium 1. Consider the following reaction, which takes place in a single elementary step: kf 2A + B A2B kr If the Equilibrium constant Kc is at a certain temperature and if kr = x 10-2 s-1, calculate the value of kf. Equilibrium Constant 2. Define Chemical Equilibrium . For a given Chemical reaction, how can you tell if the reaction is at Equilibrium ?

5 3. Consider the following Equilibrium process at 700 C: 2H2(g) + S2(g) 2H2S(g) Analysis shows moles of H2, x 10-5 mole of S2, and moles of H2S present in a L flask. a. Calculate the Equilibrium constant Kc for the reaction. b. Calculate KP for the reaction. c. Does the value of Kc indicate that there are mostly reactants or products? 4. The Equilibrium constant KP for the reaction: 2SO3(g) 2SO2(g) + O2(g) is x 10-5 at 350 C. What is Kc for this reaction? AP Chapter 14: Chemical Equilibrium & Ksp 4 5. At Equilibrium , the pressure of the reacting mixture: CaCO3(s) CaO(s) + CO2(g) is atm at 350 C.

6 Calculate KP and Kc for this reaction. 6. Ammonium carbamate, NH4CO2NH2, decomposes as follows: NH4CO2NH2(s) 2NH3(g) + CO2(g) Starting with only the solid, it is found that at 40 C the total gas pressure (NH3 and CO2) is atm. Calculate the Equilibrium constant KP. 7. Consider the reaction: 2NO(g) + O2(g) 2NO2(g) At 430 C, an Equilibrium mixture consists of mole of O2, mole of NO, and mole of NO2. Calculate KP for the reaction, given that the total pressure is atm. 8.

7 At a certain temperature the following reactions have the Equilibrium constants shown: S(s) + O2(g) SO2(g) K c ' = x 1052 2S(s) + 3O2(g) 2SO3(g) K c = x 10128 Calculate the Equilibrium constant Kc for the following reaction at that temperature: 2SO2(g) + O2(g) 2SO3(g) AP Chapter 14: Chemical Equilibrium & Ksp 5 What the Equilibrium Constant Tells about a Reaction 9. What is the difference between the Equilibrium constant (Kc) and the reaction quotient (Q)? 10. By comparing Kc and Q, how can you tell if the reaction will proceed in the forward direction, reverse direction, or is at Equilibrium ?

8 11. For the synthesis of ammonia: N2(g) + 3H2(g) 2NH3(g) the Equilibrium constant Kc at 375 C is Starting with [H2]o = M, [N2]o = M, and [NH3]o = M, which gases will increase in concentration and which will decrease in concentration when the mixture comes to Equilibrium ? 12. Consider the following Equilibrium process at 686 C: CO2(g) + H2(g) CO(g) + H2O(g) The Equilibrium concentrations of the reacting species are [CO] = M, [H2] = M, [CO2] = M, and [H2O] = M. (a) Calculate Kc for the reaction at 686 C.

9 (b) Calculate the reaction quotient to predict what happens to the concentrations of reactant and products if CO2 is added to the mixture at Equilibrium to increase its concentration to mol/L. AP Chapter 14: Chemical Equilibrium & Ksp 6 Calculating Equilibrium Concentrations and Pressures 13. Pure phosgene gas (COC12), x 10-2 mol, was placed in a L container. It was heated to 800 K, and at Equilibrium the pressure of CO was found to be atm. Calculate the Equilibrium constant KP for the reaction: CO(g) + Cl2(g) COCl2(g) 14.

10 Gaseous hydrogen fluoride can be prepared from its elements in the following combination reaction that has an Equilibrium constant (Kc) of x 102: H2(g) + F2(g) 2HF(g) In a particular experiment, mol of H2, F2, and HF were added to a L sealed flask. (a) Does the reaction proceed in the forward direction, reverse direction, or is it at Equilibrium ? (b) Calculate the Equilibrium concentrations of all species. 15. A mole quantity of NOC1 was initially in a L reaction chamber at 400 C. After Equilibrium was established, it was found that percent of the NOC1 had dissociated: 2 NOCl(g) 2NO(g) + Cl2(g) Calculate the Equilibrium constant Kc for the reaction.