Arkansas State University  Department of Chemistry and Physics
CHEM1003	Exam 3b

Exam 3b                                                                          Name_________________________
CHEM1003                                                                    Practice exam - Fall 2000
Show work on all problems for full credit

1. How many moles of S is in 6.2 moles of (NH₄)₂S₅? (8 points)
 
 
 
 
 
 
 
 

2. How many moles of CO₂ are in 2.4 x 10¹⁴ molecules of CO₂? (8 points)
 
 
 
 
 
 
 
 

3. How many moles of O would you have if you have 8.4 x 10²⁴ molecules of  CO₂?       (8 points)
 
 
 
 
 
 
 
 

4. What is the mass of 5.64 mol of F?   (8 points)
 
 
 
 
 
 
 
 
 

5. Give the empirical formula for each of the following: Be sure to circle the correct answer.  (10 points)

 a)  B₂H₆                                                 b)  Co₂(CO)₈
 
 
 

 c)  Li₂O₂                                                 d)  C₄O₂H₈
 
 
 

 e)  AlPO₄
 
 
 

6. What is the percent composition of Fe(NO₃)₃?     (10 points)
 
 
 
 
 
 
 
 
 
 
 
 
 
 

7. Determine the molecular mass for each of the following:
 Circle your answer.  (5 points each)
 

 a)  (NH₄)₃AsO₄                                     b)  Pt(ClO₄)₂
 
 
 
 
 
 
 
 
 
 

8. Determine the empirical formula for a compound from the information given:  The compound analyzes as 65.44 % C, 5.50 % H, and 29.06 % O.  (10 points)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

9. Balance the following equations by inspection.     (20 points)
 
 

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

_____ Ca(NO₃)₂  + _____ Li₂SO₄  ------>  _____ CaSO₄ + _____ LiNO₃
 
 

_____ P₄O₁₀ +  _____ H₂O   ------>  _____ H₃PO₄
 
 

_____ KOH  +  _____ CO₂    ------>   _____ K₂CO₃   +  _____ H₂O
 
 

_____ NH₃ + _____ O₂  ------>  _____ NO  + _____ H₂O
 

10. List the three parts of a chemical reaction: (5 points)
 
 
 
 
 

11. Define empirical formula (3 points)