NAME __________________________________  Please print.
 

Date ___________ day ______ time __________

Dr. H.J. Plastas

This is an open book, 22 problem, take home exam. It is due at the next class meeting. Try to work the exam without your book. Then go through it the second time using references. Mail it to Dr. H. Plastas Chemistry Department, Montgomery College, Rockville, MD 20850 if you can not attend that class. Mail it if you are in a distance learning section. By signing below your are attesting, on your honor, that you have completed this exam without help from any other person.
 

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1. ___H₂O + ___Ca₃P₂(s) --> ___PH₃ + ___Ca(OH)₂
 

2. ___H₂O + ___Br₂ + ___H₂S --> ___H₂SO₄ + ___HBr
 

3. ___C₉H₁₁ + ___O₂ --> ___CO₂ + ___H₂O
 

4. ___TiO₂ + ___H₃SbO₄ --> ___Ti₃(SbO₄)₄ + ___H₂O
 

5. ___Sb₂S₃ + ___PbO --> ___Sb₂O₃ + ___Pb + ___SO₂
 

Complete and balance (using the smallest whole number ratio) the following equation. If no reaction will take place write "NR". (4 pts each)
 

6. ___Cl₂O₅ + ___H₂O --->
 

7. ___Ti(ClO₃)₃(s) >
 

8. ___Sn₃(PO₄)₄ + ___Ba -->
 

9. ___P₂O₃ + ___ KOH -->
 

10. ___H₂SO₄(aq) + ___ Fe₂O₃(aq) -->
 

11. ___AlCl₃ + ___Ba(OH)₂ -->
 

12. ___V₂(CO₃)₃(s) >
 

13. ___C₅H₁₀O₅ + ___O₂ (in excess) -->
 

14. ___(NH₄)₂SO₄(s) >
 

15. ___Fe(CN)₃(s) ___ HCl(aq) -->
 

For the remaining problems, show the set up and give the answer to the proper number of significant figures with the correct units. Neatness will be greatly appreciated! Box the answer.

16. Convert 0.0991 lb. of zinc to moles. (7 pts)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

17. Convert 880 cg of iodine to molecules. (7 pts)
 
 
 
 
 
 
 
 
 
 
 

18. Calculate the percent by weight of sulfur in arsenic(III)

sulfide, to three significant figits. (7 pts)
 
 
 
 
 
 
 
 
 

19. An experimental catalyst used in the polymerization of butadiene is 23.3% Co, 25.3% Mo and 51.4% Cl.

Calculate its empirical formula. (10 pts)
 
 
 
 
 
 
 
 
 

20. What is the molecular formula of a compound

with the empirical formula C₃H₆O₂ and molar

mass of approximately 887 grams per mole. (5 pts)
 
 
 
 
 
 
 
 

21. Suppose a new element is discovered, atomic number 114, consisting of two isotopes. The lighter isotope is 88.444% abundant and weighs 280.91 amu/atom. The heavier isotope weighs 284.11 amu/atom. Calculate the atomic weight (atomic mass) to 5 significant figures. (7 pts)
 
 
 
 
 
 
 
 
 
 

22. If gold is selling for $4700 a pound, how many atoms

of gold can be bought for one cent? (7 pts)