Chemist:_______________________________________ Date:____________________ Class period:_____
AP Chemistry: Practice Test
Chapter 3
Multiple Choice
_______1. The molecular weight of ethylene glycol, C2H6O2 is closest to
A. 29 g
D. 62 g
B. 50 g
E. 94 g
C. 34 g
_______2. A sample of fructose, a fruit sugar, C6H12O6, that contains 24 g of carbon, would also contain
___ grams of oxygen.
A. 24 g
D. 48 g
B. 64 g
E. 32 g
C. 96 g
_______3. How many moles of SO3 are in a 24 g sample?
A. 56
B. 1920
D. 0.60
E. 12
C. 0.30
_______4. Which of the following contains the greatest mass of oxygen?
A. 1.0 mol of O2
D. 1.0 mole of KClO3
B. 0.50 mole of Na2S2O8
E. 0.50 mole of K2Cr2O7
C. 1.0 mole of O3
_______5. What is the percentage of silver in silver oxide, Ag2O?
A. 12.9 %
D. 87.1%
B. 93.1%
E. 6.90%
C. 78.1%
_______6. The mineral leadhillite, which is Pb4(SO4)(CO3)2(OH)2 contains ____% oxygen by mass.
A. 17.8
D. 14.8
B. 13.3
E. 10.4
C. 11.9
_______7. A hydrocarbon found in fuel is analyzed and found to contain 84.2 % carbon and 15.8% hydrogen
by mass. What is its empirical formula?
A. CH2
D. C3H8
B. C8H18
E. C5H12
C. C4H9
_______8. Aspirin (C9H8O4), which many students take after a chemistry exam, is prepared by the reaction of
salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). How many grams of salicylic acid are required to
prepare one tablet containing 0.325 g of aspirin?
C7H6O3 + C4H6O3 → C9H8O4 + C2H4O2
salicylic acid
aspirin
A. 0.249 g
D. 0.325 g
B. 0.424 g
E. 2.36 g
C. 0.847 g
_______9. If 100. g of O2 are mixed with 100. g of H2 and the mixture is ignited, what mass of water is
produced?
A. 56 g
D. 900 g
B. 113 g
E. 200 g
C. 100 g
_______10.The products of the combustion of acetaldehyde with oxygen are shown in the following equation:
_____ CH3CHO
+
_____ O2
→
_____ CO2
+
_____ H2O
When properly balanced, the equation indicates that ___ moles of O2 are required for each mole of
CH3CHO
A. 1
D. 2.5
B. 2
E. 5
C. 3
Problems
11. Is the spectrum on the right the mass spectrum of potassium or calcium?
Justify your reasoning.
12. Chlorophyll-a, the green coloring matter of plants contains 2.72% Mg. If each formula unit of
Chlorophyll-a has one Mg atom, what is the molar mass of chlorophyll-a?
13. Gallium consists of two isotopes of masses 68.95 amu and 70.95 amu with relative abundances of 60.16%
and 39.84% respectively. What is the atomic mass of gallium?
14. A sample of a compound that contains only carbon, hydrogen and sulfur was burned in oxygen and
9.682 g of CO2, 4.956 g of H2O and 3.523 g of SO2 were obtained. What is the empirical formula of the
compound?
15. Assume that 45.67 g of potassium chromate reacts with 89.52 g of zinc phosphate to produce potassium
phosphate and zinc chromate.
a) Write and balance the chemical equation for this reaction.
b) What is the limiting reactant in this problem?
c) What mass of the zinc chromate is (theoretically) produced?
d) If 27.9 g of zinc chromate is actually produced, what is the percent yield of zinc chromate?
e) What mass of the excess reactant is left over (unreacted)?