Arkansas State University  Department of Chemistry and Physics
CHEM1003	Exam 4

1. Given the following equation:    (10 points)

_____ La₂O₃  + _____ H₂O   --------> _____ La(OH)₃

 a)  Balance the equation.

 b) If you start with 3.5 moles of H₂O, how many moles of La(OH)₃ is produced?
 
 
 
 
 
 
 
 

 c) If you start with 2.75 moles of La₂O₃, how many moles of La(OH)₃ is produced?
 
 
 
 
 
 
 
 

 d) If you start with 2.40 g of La₂O₃, how many grams of La(OH)₃ is produced?
 
 
 
 
 
 
 
 
 
 

2. Describe the parts of a solution.  (5 points)
 
 
 
 

3. Given the following equation                       (20 points)

  H₂SO₄    +     2 NaOH    ------>  Na₂SO₄    +  2 H₂O

a) If 49.0 g of H₂SO₄ is reacted with 20.0 g of NaOH, determine the limiting reagent
 
 
 
 
 
 
 
 
 
 
 
 
 
 

b)   Determine the number of moles of H₂O produced
 
 
 
 
 
 

c)   Determine the number of grams of Na₂SO₄ produced
 
 
 
 
 
 
 
 
 
 

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

4. Given the following equation

  Mg₃N₂    +  8 HCl  ------> 2 NH₄Cl    +  3 MgCl₂

If you start with 57.4 g of Mg₃N₂ and you isolate 22.4 g of MgCl₂, what is your percent yield for this reaction?  (10 points)
 
 
 
 
 
 
 
 
 
 
 
 
 

5. Determine the molarity of the solution containing 3.0 mol of NaOH in 150 mL total volume of solution.  (6 points)
 
 
 
 
 
 
 
 

6. Determine the number of moles of NaOH in 500 mL of a 6.0 M NaOH solution.      (6 points)
 
 
 
 
 
 
 
 

7. What is the volume of 1.5 M NaI needed to have 1.25 mol NaI? (6 points)
 
 
 
 
 
 

8. How many grams of Cu(NO₃)₂ is needed to make 200 mL of a 1.2 M Cu(NO₃)₂ solution?    (6 points)
 
 
 
 
 
 
 
 

9. How do you prepare 1000 mL of a 0.4 M KClO solution?
 (10 points)
 
 
 
 
 
 
 
 
 
 
 

10. How would you prepare 250 mL of a 1.6 M H₂SO₃ solution if you start with a 2.4 M H₂SO₃ solution?            (10 points)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

11. Define the terms dilute and concentrated.  What problem(s) may occur when using these terms?    (5 points)
 
 
 
 
 

12. Given the following equation    (6 points)

 Ca(OH)₂ (s)   +  2 HBr (aq)  ------->   CaBr₂ (aq)   +   2 H₂O (l)

 If 25.4 mL of 2.4 M HBr is spilled on the lab floor and all you have to neutralize the spill is solid Ca(OH)₂, how many grams would you need to react with all of the HBr?