**This is a sample Final Exam given in chem 050 in 1988 at
the University of Idaho**

Problem Set #3

Due: November 29, 1988

SHOW ALL WORK using DIMENSIONAL ANALYSIS SET UPS on the problems.

1. (10 pts) If 15.3 g of Fe_{2}O_{3}
produces 10.0 g of Fe, according to the equation

**Fe _{2}O_{3} + 3 CO --> 2 Fe + CO_{2}**,

What is the percent yield of the reaction?

2. (5 pts) In the reaction

**2 AgNO _{3} + K_{2}S --> Ag_{2}S
+ 2 KNO_{3}**,

calculate the grams of K_{2}S needed if a 8.0% excess is supplied
in a reaction with 84.6 miligrams AgNO_{3}.

3. (5 pts) A 0.551 gram sample composed of Ag2S and inert matter yielded 0.438 grams pure AgCl. Calculate the percent Ag2S in the original sample.

4. (10 pts) For the sequence of reactions

__FeCr _{2}O_{4}__ + 8 HCl -->
FeCl

__CrCl _{3}__ + 4 NaOH --> 3 NaCl +

__2 NaCr(OH) _{4}__ + 3 H

calculate the pounds of FeCr_{2}O_{4} consumed if 138
pounds of Na_{2}CrO_{4} are produced.

5. (10 pts) A solution is prepared by mixing 24.6 grams H_{2}SO_{4}
with 48.4 grams H_{2}O. The resulting solution has a density of 1.32
g/mL.

a) Calculate the molarity of the solution.

b) Calculate the molality of the solution.

6. (10 pts) a) Calculate the milliliters of 0.200 M Mg(OH)_{2}
solution needed to react with 32.7 mL of 0.156 M HCl solution by the reaction

**Mg(OH) _{2} + 2 HCl --> MgCl_{2} + 2
H_{2}O**

b) Calculate the molarity of an HNO_{3} solution if 16.4 mL were
needed to react with 0.124 grams of (NH_{4})_{2}CO_{3}
by the reaction:

**2 HNO _{3} + (NH_{4})_{2}CO_{3}
--> H_{2}O + CO_{2} + 2 NH_{4}NO_{3}**

7. (10 pts) a) Calculate the milliliters of 1.00 M CdCl_{2}
solution needed to prepare 756 mL of 0.225 M solution.

b) Calculate the molarity of a solution prepared by mixing 845 mL 5.00 M HBr soluion with 325 mL 1.5 M HBr solution.

8. (5 pts) Calculate the mL of 23.4% Cu(NO_{3})_{2}
solution having a density of 1.21 g/mL needed to completely react with 34.9
grams of KI in the reaction

**2 Cu(NO _{3})_{2} + 5 KI --> 2 CuI +
KI_{3} + 4 KNO_{3}**

9. (5 pts) Calculate the milliliters of 98.0% H_{2}SO_{4}
solution having a density of 1.84 g/mL needed to make 275 mL of 40.0% H_{2}SO_{4}
solution having a density of 1.40 g/mL.

10. (10pts) __Using logarithm tables__, calculate the
answer for the following expression. (Show all calculations).

2.13 x 10^{5})(46.3 x 10^{-3})/(0.317)(8.641
x 10^{2})

11. (10 pts) __Using logarithms__, evaluate the following.
(Show all work.)

a) (6561)^{1/3}

b) (0.0003181)^{5}

12. a) (5 pts) __Using logarithms__, find the pH of a
solution that has [OH^{-}] = 6.89 x 10^{-10} molar.

b) (5 pts) __Using logarithms__, calculate the p[OH] of a
solution where 480.3 mL of the solution contain 5.66 x 10^{-6} mols of
hydrogen ion. (Show all work.)