Memorized
Mole Triangle Conversions
Limiting Reactant Problem Process
Empirical/Molecular Problem Process
Unit 5 Practice Test
Format
No Multiple Choice or Short
answer responses!
All problem-based!
Provided
Periodic Table
Activity Series
Part I
1. When the following equation is balanced, the coefficients are
_______________.
Al(NO3)3 + Na2S  Al2S3 + NaNO3
A) 2, 3,1,6
B) 2, 1, 3, 2
C) 1, 1, 1, 1
D) 4, 6, 3, 2
E) 2, 3, 2, 3
2. There are _______ sulfur atoms in 25 molecules of C4H4S2.
A) 1.5 x 1025
B) 4.8 x 1025
C) 3.0 x 1025
23
D) 50
E) 6.02 x 10
Coverage
Unit 5, Lessons 1-5
Chemical Equation Terminology,
Balancing Chemical Equations,
Identifying Types of Reactions (Synthesis,
Decomposition, Single Replacement, Double
Replacement, Combustion),
Predicting Products,
Calculating Formula Weight,
Determining Percent Composition,
Hydrates,
Converting between Moles, Grams, Liters,
and Representative Particles,
Converting between Moles and Moles,
Theoretical Yield vs. Actual Yield,
Limiting Reactant Problems,
Empirical vs. Molecular Formulas,
Determining/Deriving Empirical/Molecular
Formulas.
3. A compound that is composed of only carbon and hydrogen contains 80.0% C and 20.0% H by mass. What is the
empirical formula of the compound?
A) C20H60
B) C7H20
C) CH3
D) C2H6
E) CH4
4. The formula weight of magnesium fluoride (MgF2) is __________ amu.
A) 86.6
B) 43.3
C) 62.3
D) 67.6
5. The mass % (percentage composition) of F in the binary compound KrF2 is __________.
A) 18.48
B) 45.38
C) 68.80
D) 81.52
E) 92.9
E) 31.20
Part II
Write balanced chemical equations and identify the type of reaction for each of the following:
1. zinc metal reacts with copper (II) bromide to yield zinc bromide and copper metal
2. potassium chlorate decomposes to produce potassium chloride and oxygen gas
3. indium metal reacts with oxygen gas to yield indium (III) oxide
4. potassium metal reacts with fluorine gas to yield potassium fluoride
5. lithium hydroxide reacts with carbon dioxide to produce lithium carbonate and water
Part III
Identify the type of reaction if it is not provided, then predict the products for the following equations. You will need to
use the metal activity series for some equations.
1. Synthesis:
Mg
+
I2

2. Double displacement:
CuCl2
+
H2S

3. Double displacement:
NaOH
+
HClO4 
4. Decomposition:
ZnCO3 +
heat

5. Single replacement:
HCl
Zn

+
6. Combustion:
C6H12
+
O2

7. Combustion:
C4H6
+
O2

8. Combustion:
C6H10O3
+
O2

9. ________________
Na
+
MgCl2 
10. ________________
CaCl2
+
K2CO3 
11. ________________
BaCl2
+
K3PO4 
12. ________________
Pb(NO3)2
+
KOH
13. ________________
H2SO4 +
BaCl2

14. ________________
Ca
+
AgCl

15. ________________
H3PO4 +
FeBr3


Part III
1. Copper can be extracted from copper (II) oxide by reduction with methane. The unbalanced reaction is:
CuO + CH4  Cu + CO2 + H2O. Calculate the amount of copper in particles than can be produced from
100.0 grams of Copper (II) oxide.
2. When nitrogen gas reacts with hydrogen gas, liquid ammonia is formed: N2 + H2  NH3. How
many liters of ammonia could be collected from the reaction of 12.5 grams of nitrogen with 14.3 grams of
hydrogen?
3. Silver nitrate solution reacts with calcium chloride solution to produce aqueous calcium nitrate and silver chloride
precipitate, AgNO3 + CaCl2  Ca(NO3)2 + AgCl
(a) Suppose we mix together a solution containing 6.30 g of silver nitrate and one containing 4.20 g of calcium
chloride. What mass of silver chloride should we expect to produce?
(b) If only 0.05 moles of silver chloride were actually obtained, what is the percent yield?
4. When iron (III) oxide reacts with solid aluminum metal, a highly energetic reaction occurs that produces solid iron
metal and aluminum oxide, Fe2O3 + 2 Al  2 Fe + Al2O3
(a) If 500 grams of iron (III) oxide reacts with 500 grams of aluminum, what is the theoretical yield of iron?
(b) How much excess reagent will remain when the reaction is finished?
(c) If this explosive thermite reaction only produced 166.5 grams of iron metal, what is the reaction’s percent yield?
5. Solutions of sodium sulfate, Na2SO4 and lead(II)chloride, PbCl2, are combined to produce solid lead(II) sulfate, PbSO4,
and sodium chloride, NaCl solution.
(a) Write a balanced equation for the reaction described above.
(b) If the solutions contained 7.50 grams of sodium sulfate and 11.30 grams of lead(II)chloride, what is the
limiting reagent?
(c) What amount, in grams, of the excess reagent is left over?
(d) If the reaction described above was performed experimentally and the % yield of lead (II) sulfate was 87.3%,
what mass, in grams, of the solid was recovered?
6. The empirical formula for caffeine, a natural stimulant in coffee and tea, is C4H5N2O. The molar mass of caffeine is
194.2g .
(a) What is the molecular formula for caffeine?
(b) Calculate the percent composition of nitrogen in caffeine.
(c) If there are 50 mg of caffeine in a cup of coffee, how many molecules is that?
7. An active ingredient in photographic fixer contains 29.2% sodium, 40.5% sulfur, and 30.3% oxygen. What is the empirical
formula of this substance?
8. Calculate the number of C, H, and O atoms in 1.50 g of glucose (C6H12O6).
9. Cinnamic alcohol is used mainly in perfumery, particularly in soaps and cosmetics. Its molecular formula is C9H10O.
Calculate the percent composition by mass of C, H, and O in cinnamic alcohol.
10. Perform each of the following conversions:
a. 26.5 g of MgCl2 to moles of MgCl2
b. 2.22 mol of O2 of molecules O2
c. 6.57 x 1018 atoms of Fe to grams of Fe
d. 3.456 mol of CH4 to grams of CH4
e. moles of nitrogen in 6.50 mol ammonium phosphate, (NH4)3PO4
11. How many moles of water will be formed in the complete combustion of 2.50 mol of methane, CH4?
12. When 100 g of FeCl3 reacted with 50.0 g of H2S, how many grams of which reactant will be left over when the
reaction is complete?
13. In the lab, you decide to combine 125.2 g of aqueous calcium chloride with 20.g of solid sodium.
A. Write and balance the equation for the reaction described above.
B. If the percent yield for calcium was 92%, calculate the actual yield for calcium.
C. Calculate the remaining amounts of each reactant after the reaction finishes.
14. DDT, an insecticide harmful to fish, birds, and humans is produced by the following reaction:
C6H5Cl
+
C2HOCl3

C14H9Cl5
+
H2O
chlorobenzene
chloral
DDT
In a government lab, 1142g of chlorobenzene is reacted with 485g of chloral.
A. Which reactant is the limiting reactant?
B. What mass of DDT is formed?
C. What mass of the excess reactant is left over? (4 points)
D. If the actual yield of DDT is 200.0g, what is the percent yield?
E. What might have gone wrong?