Arkansas State University 
Department of Chemistry
and Physics
CHEM1013
Exam 2
(Note: only the questions are listed, spaces have been removed for brevity)

SHOW WORK ON ALL PROBLEMS

1.  Balance the following equations by inspection.        (12 points)

         Zn  +           HCl   ------->           ZnCl2   +            H2

         RbOH  +           SO2   ------->           Rb2SO3  +            H2O

         Ba(OH)2  +           P4O10   ------->           Ba3(PO4)2   +            H2O

2. Given the equation:   (12 points)

Au2S3   +   3 H2  -------->   3 H2S    +  2 Au

a) determine the number of moles of Au that could be produced from 4.3 mol Au2S3

b) determine the number of grams of H2S that could be produced from 4.3 mol Au2S3

c) determine the number of grams of H2S that could be produced from 12.5 g Au2S3

3. Given the following equation:        (10 points)

Li2SO4    +   BaCl2  ------->   2 LiCl   +   BaSO4

If you start with 244 g of Li2SO4 and you isolate 72.4 g of LiCl, what is your percent yield?

4.  What is the percent composition of Ba(OCN)2?        (10 points)

5.  Determine the empirical formula for a compound that analyzes as 67.25% C, 6.60 % H and 26.15 % N.  (10 points)

6.   Given the equation:              (20 points)

H3PO4   +  3 KOH  ------>  K3PO4 +  3 H2O

a) If 49.0 g of H3PO4 is reacted with 56.1 g of KOH, determine the limiting reagent

b) Determine the number of moles of H2O produced

c) Determine the number of grams of K3PO4 produced

d) Determine the number of grams of excess reagent left over in the reaction

7.  Given the following equation:           (6 points)

2 HClO4    +   Ca(OH)2  ------->   2 H2O   +   Ca(ClO4)2

If you start with 50 mL of a 3.0 M HClO4 solution and have an excess of the Ca(OH)2 solution, determine the amount (in grams) of Ca(ClO4)2 that can be produced in this reaction.

8.  How would you prepare 75 mL of a 0.56 M solution of Ca(OH)2 ?     (8 points)

9.  Given the following equation:    (8 points)

AgNO3    +   KCl  ------->    AgCl   +   KNO3

a)  If 75.4 mL of a 1.2 M AgNO3 is reacted with excess KCl, how many grams of AgCl was prepared in this reaction?

b)  If 92.4 mL of KCl was used to react with the 75.4 mL of a 1.2 M AgNO3, what is the original concentration of KCl?

10.  What volume of 18.0 M H2SO4 is needed to prepare 1.2 L of 6.0 M H2SO4 solution?   (4 points)