Answer the following questions that relate to solubility of salts of lead and barium:
A) A saturated solution is prepared by adding excess PbI2(s) to distilled water to form 1.0 L of solution at 25C. The concentrations of Pb2+ (aq) in the saturated solution is found to be 1.3 x 10^-3 M. The chemical equation for the dissolution of PbI2 (s) in water is shown below
PbI2 = Pb2+ (aq) + 2 I- (aq)
B) A saturated solution is prepared by adding PbI2(s) to distilled water to form 2.0 L of solution at 25C. What are the molar concentrations of Pb2+ (aq) and I-(aq) in the solution? Justify your answer
C) solid NaI is added to a saturated solution of PbI2 at 25C. Assuming that the volume of the solution does not change, does the molar concentration of Pb2+(aq) in the solution increase , decrease or remain the same?. Justify your answer
D) the value of Ksp for the salt BaCrO4 is 1.2 x 10^-10. When a 500ml sample of 8.2 x 10 ^-6 M Ba( NO3)2 is added to 500ml of 8.2 x 10^-6 M Na2CrO4 , no precipitate is formed
(i). Assuming the volumes are additive, calculate the molar concentration of Ba2+ (aq) and CrO4 (aq) in the 1.00 L solution.
(ii). Use the molar concentrations of Ba2+ (aq) ions and CrO4 2- (aq) ions as determined above to show why a precipitate does not form. You must include a calculation as part of your answer.
The solution analyzes the equilibriums of PbI2 and BaCrO4 solutions, respectively.
Aqueous Ionic Equilibrium 2
Aqueous Ionic Equilibrium 2
1- Which of the following processes will result in an increase of entropy of the system? Choose from:
2- What does the standard change in Gibbs free energy ( ) of a reaction tell us about the equilibrium constant (K) for that reaction under standard conditions? Choose from:
There is no significant relationship between and K.
A negative indicates that product formation is favored, and K will be greater than 1.
A negative indicates that reactant formation is favored, and K will be less than 1.
3- Which of the following combinations of and describe a process that is only spontaneous at low temperatures? Choose from:
: positive , : positive
: negative , : positive
: positive , : negative
: negative , : negative
Spontaneity is not related to the sign of and .
4- AB 2 has a molar solubility of 3.72×10 −4 M . What is the value of the solubility product constant for AB2 ?
5- C 2 D 3 has a solubility product constant of 9.14×10 −9 . What is the molar solubility of C 2 D 3 ?
6- A buffer contains significant amounts of ammonia and ammonium chloride.
Part A:Write an equation showing how this buffer neutralizes added acid (HI)
Part B: Write an equation showing how this buffer neutralizes added base (CsOH). Express your answer as a chemical equation.
7- Solve an equilibrium problem (using an ICE table) to calculate the pH of each solution:
Part A: a solution that is 0.165M in HC 2 H 3 O 2 and 0.120M in KC 2 H 3 O 2
Part B: a solution that is 0.185M in CH 3 NH 2 and 0.110M in CH 3 NH 3 Br
8- A 1.0-L buffer solution is 0.105M in HNO 2 and 0.145M in NaNO 2 . Express your answers using three significant figures separated by a comma.
Part A: Determine the concentrations of HNO 2 and NaNO 2 after addition of 1.4g HCl
Part B: Determine the concentrations of HNO 2 and NaNO 2 after addition of 1.4g NaOH .
Part C: Determine the concentrations of HNO 2 and NaNO 2 after addition of 1.4g HI.