Answers
1. Sketch a rough plot of pH versus volume of base added for the titration of 30mL of 0.500 M HI
with 0.300M NaOH.
a. What is the pH before any NaOH is added?
b. What is the pH after 30mL of the NaOH is added?
c. What is the volume of base in mL needed to reach the equivalence point? What is the
pH here?
d. What is the pH after 107% of the required base is added?
2. Dissolve 0.366g of CH3CO2H in enough water to make 100mL of solution. Then titrate the
solution with a 0.299M solution of NaOH. (only 3 sig. figs)
a. What is the pH before any NaOH is added?
b. What is the pH after 10.2 mL of NaOH is added?
c. What is the pH after 14.25mL NaOH is added?
d. What is pH after 20.4 mL NaOH added?
e. What is pH after 25mL NaOH added?
Answers Part 2
3. What is the solubility of BaSO4 in the presence of 0.010M Ba(NO3)2. Ksp for BaSO4 is 1.1×10-10.
4. Decide if each of the following is water-soluble. If it is, then tell what ions are made.
a. Na2CO3
b. CuSO4
c. NiS
d. Pb(NO3)2
e. BaBr2
f. NiCl2
5. If you put 1.234g of solid Ca(OH)2 into 1.00 L of pure water at 25oC, the pH of the solution is
found to be 12.68. What is the value of Ksp for Ca(OH)2?
Answers Part 3
6. If you have 75mL of a solution that has a lead (II) concentration of 0.0012M, will PbCl2 precipitate
when 1.20g of solid NaCl is added? Ksp = 1.7×10-5
7. The cations below appear together in an aqueous solution. Add only one reagent to precipitate one
cation and not the others. Add the reagents in a sequence so all the cations do not precipitate at
once.
Ag+, Pb2+, Be2+, Na+
8. Calculate the ∆G at 500K for the following reaction:
(1/2)N2(g) + (3/2)H2)g) → NH3(g)
∆So (J/K×mol)
∆Ho (kJ/mol)
N2(g)
191.56
0
H2(g)
130.7
0
NH3(g)
192.77
-45.90
9. Using values for ∆Gof from Appendix L in the back of the book, find ∆Gorxn. Is the reaction product
favored?
SiCl4(g) + 2Mg(s) → 2MgCl2(s) + Si(s)
10. Calculate the ∆Go and K at 25oC for the reaction
HBr(g) + Cl2(g) → 2HCl(g)
Is the reaction product favored?
11. Balance the following redox equation that occurs in a basic solution:
Al(s) + OH-(aq) → Al(OH)4-(aq) + H2(g)
Should come out with same number of atoms on both sides and same charge on both sides.
12. Balance the following redox equation that occurs in an acidic solution:
MnO4-(aq) HSO3-(aq) → Mn2+(aq) + SO42-(aq)
Should come out with same number of atoms on both sides and same charge on both sides.
13. Calculate the Eo for the following reaction (use the sheet from class)
Sn2+(aq) + Ag(s) → Sn(s) + Ag+(aq)
14. The ∆Eo value for the following reaction is -0.76 V. Calculate ∆Go for the reaction. Is this rxn.
product favored for reactant favored?
15. A radioactive decay series begins with
and ends with
. The first three steps of the
reaction in order are α, β and α emission. Write an equation for each of these steps.
16. What is x in these equations? Give the symbol, mass number and atomic number.
a.
b.
c.
17. Iodine-131 is a beta emitter and has a half-life of 8.04 days.
a. Write an equation for the decomposition of I-131