PART I - Multiply Choice
Directions: Using Scantron 882-E, mark the correct response with a #2 pencil. Erase all corrections completely. Good luck!
1. A really smelly compound called putrescine is isolated from rotting flesh. It is composed of carbon, hydrogen and nitrogen. The percentage of carbon is 54.5% and the percentage of hydrogen is 13.6% hydrogen. Its true molecular formula has a molar mass of 88.0 g/mole. What is its molecular formula?
a. C4HN2 b. C12H3N7 c. C4H12N2 d. C2H6N e. C4H6N
2. Under special conditions, silicon reacts with nitrogen to yield a white powder of silicon nitride.
3 Si(s) + 2 nitrogen (g) yields Si3N4(s)
How many grams of Si3N4 can be produced when 46.0 g of silicon and 35.0 g of nitrogen are combined?
a. 164 b. 87.6 c. 76.6 d. 11.0 e. 81.0
3. How many hydrogen atoms are there in 0.500 mole of ammonium phosphate?
a. 1.81 x 1024
b. 4.21 x 1024
c. 3.61 x 1024
d. 2.11 x 1024
e. 3.01 x 1023
4. Potasium iodide reacts with lead(II) nitrate to produce (you know)
An excess of lead(II) nitrate was reacted with 15.0 g of potassium iodide. A mass of 10.0 g of lead(II) iodide was recovered. What is the percent yield of lead(II) iodide?
a. 24.0% b. 48.0% c. 100% d. 66.7% e. 20.8%
5. Which of the following atomic symbol is incorrect?
a. 139 Ba
b. 48 Ti
21
c. Iron - 56
d. 14 Li
3
e. Nitrogen -14
6. How many atoms of oxygen are there in 0.660 mole of oxygen?
a. 3.97 x 1023
b. 0.660 x 1023
c. 1.25 x 1023
d. 7.95 x 1023
e. 1.27 x 1025
7. The empirical formula of the compound containing 31.0% titanium (atoms) and 69.0% chlorine (atoms) is
a. TiCl b. TiCl2 c. TiCl3 d. TiCl4 e. TiCl5
8. A student prepares ethyl bromide, (C2H5Br), by heating ethyl alcohol, (C2H5OH), with aqueous hydrobromic acid via the following reaction:
C2H5OH (l) + hydrobromic acid produces C2H5Br (l) + water
The student starts with 60.0 g of ethyl alcohol and excess hydrobromic acid. The actual yield is 100.0 g of ethyl bromide. What is the percent yield of ethyl bromide?
a. 70.4 % b. 142 % c. 29.6 % d. 1.42 % e. 42.0 %
9. A beaker has a mass of 42.172 g. When 5.00 mL of a salt solution is placed into the beaker, the mass of the beaker plus salt solution is 48.977g. What is the density of the salt solution?
a. 1.3600 g/mL b. 9.80 g/mL c. 8.43 g/mL d. 0.735 g/mL e. 1.36 g/mL
10. What mass of carbon dioxide is produced if 12.0 g of carbon and 12.0 g of oxygen are allowed to react according to the following balanced chemical equation?
C + O2 ® CO2
a. 60.5 g b. 44.0 g c. 16.5 g d. 24.0 g e. 12.0 g
11. When methane burns, how many grams of methane will react with 125 g of oxygen?
a. 39.1 g b. 19.5 g c. 15.6 g d. 31.3 g e. 62.5 g
PART II - Free Response
Table I: Reactions
Directions: Write the balanced equation for the following reactions. Use only the following descriptions: neutralization, precipitation, single displacement, gaseous, combustion, synthesis or decomposition ONLY.
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Reaction |
Balance Equation ( place states on the products only) |
Description |
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Propanol (aq) (C3H7OH) burns
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Aqueous magnesium sulfide reacts with aqueous barium hydroxide |
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Sulfuric acid reacts with aqueous barium hydroxide
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Aqueous sodium hydrogen carbonate reacts with hydrochloric acid
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Aqueous lithium sulfate reacts with nitric acid
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Table II. VSEPR Table: Complete the following table using IUPAC nomenclature only.
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Name |
Formula |
Molecular Shape of Molecule or Polyatomic Ion ( Name Only) If None Write None |
Molecular Polarity Molecule or Polyatomic Ion (Write Yes or No) If None Write None |
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Barium sulfite
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Sodium nitrate
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Hydrogen sulfide gas
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Oxygen
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CH4
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Carbon dioxide gas
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Part III: Write the balanced equation for each of the following situations. Describe the reaction type by writing the letter of the reaction type in the space provided on the answer key. Identify the limiting reactant (if any) and determine the grams of each resulting product.
Reaction Type
Key:
a. Combination Reaction
b. Decomposition Reaction
c. Single Replacement Reaction
d. Precipitation Reaction
e. Gaseous Reaction
f. Neutralization Reaction
g. Combustion Reaction
1. 3.02 g of potassium chlorate is heated to form potassium chloride and oxygen
2. 61.8 g of nitrogen gas is reacted with 61.8 g of hydrogen gas to form ammonia
3. 1.839 g of calcium hydroxide is reacted with a solution of sulfuric acid
4. 0.0123 g strip of zinc is dropped into a test tube of hydrochloric acid
5. 2.11 g of hydrogen peroxide decomposes in the presence of manganese dioxide to form water and oxygen
6. 8.9 g of copper(II) sulfate, pentahydrate is heated to drive off the water of hydration
7. A 4.32 g sample of methane burns in excess oxygen
8. 5.92 g of sodium oxalate is reacted with 6.76 g of calcium chloride
9. 3.33 g of barium chloride is reacted with 3.34 g of sulfuric acid
10. 1.29 g of sodium chloride is reacted with 3.94 g of silver nitrate
11. 3.5 g of barium nitrate is reacted with 1.222 g of sodium sulfate
12. 1.3 g strip lithium reacts with 3.3 g of magnesium nitrate
13. 6.9 g sodium nitride forms sodium and nitrogen gas
14. 3.5 g silver nitrate reacts with 3.9 g of aluminum
15. 1.95 g iron(III) chloride and 2.35 g of sodium hydroxide
Part III: Balancing Equations
1. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
2. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
3. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
4. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
5. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
6. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
7. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
8. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
9. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
10. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
11. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
12. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
13. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
14. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
15. Balanced Equation
_____________________________________________________________________________________
Reaction
Type________
Limiting Reactant _____________________________
Grams of Product (List the Product and the Amount)
_____________________________________________________________________________________
Part IV: Determine the percent composition of each element in the following compounds.
1. lithium nitride, pentahydrate
2. sodium phosphate
3. cesium oxide
4. calcium permanganate
5. iron(III) nitrate, hexahydrate
Part IV: Percent Composition
1. Li____________, N______________, H_______________, O______________
2. Na____________, P_______________, O________________
3. Cs____________, O_______________
4. Ca____________, Mn______________, O_______________
5. Fe_____________, N_______________, O______________, H_______________