2. What is the % mass of carbon in carbon dioxide?
44% 25% 27% 63% 50%
3. Substance X has a mass of 36.08 grams. Calculations show that .199 moles of substance X exist. What element is most likely X?
Molybdenum Technetium Ruthenium Rhodium Palladium
4. Substance A combines with substance B to form Substance AB. B is a diatomic molecule. You are given 3.15 moles of B2. If A is in excess, how many moles of AB are produced?
1.20 2.30 3.25 5.60 6.30
5. How many moles in 20 g of water?
1.11 20 18 1.1 42
6. A chemistry student was performing an experiment involving the following reaction: C3H8 (g) + O2 (g) --> CO2 (g) + H2O (g), balancing it with the coefficients 1, 5, 2, and 4 respectively. The oxygen was in excess. He used 20.18 grams of C3H8. When he measured the amount of CO2 produced, he was astounded to find that 46.22 grams were produced, 5.88 grams more than the theoretical yield of 40.34. What went wrong? Hint: Look at the formula
C3H8's coefficient should be 3, not 1 CO2's coefficient should be 3, not 2 O2's coefficient should be 3, not 5 Water's coefficient should be 3, not 4 None of these
7. The empirical formula of a compound is C10H20 with a molar mass of 284 grams, find the molecular weight.
C20H40 C10H20 C5H10 C4H8 CH4
8. Ferric chloride can be made by the reaction of iron with chlorine gas. How much mass, in grams, is needed to completely react with 24.0 g chlorine gas?
12.59 24.0 48.0 12.6 48.01
9. If 11 grams in a reaction was obtained, and you had a theoretical yield of 14 grams, what is your % yield?
0.79% 79% 11% 14% 12%
10. Hydrochloric acid reacts with calcium carbonate yielding calcium chloride, water, and carbon dioxide. How many moles of calcium carbonate would be necessary to react with 8 moles of HCl?
1 2 3 4 5
11. When aluminum reacts with sulfuric acid, the result is aluminum sulfate and hydrogen gas. How many moles of sulfuric acid (H2SO4) will react with 24 moles of aluminum?
12 14 16 18 20
12. The formation of ammonia is shown by the following reaction: N2 (g) + 3H2 (g)--> 2NH3 (g). You are given 13.85 grams of nitrogen and 5.27 grams of hydrogen. If the experiment produced 3.297 grams of ammonia, then what is the percent yield?
25% 50% 35.80% 76.60% None of these
13. What is the mass percent of oxygen in H2SO4 (sulfuric acid)?
0 1% 2.04% 32.70% 65.26%
14. There are 2.34 moles of substance A3 combined with 2.77 moles of substance B. Assume that the reaction goes to completion. After the reaction is complete, AB is reacted with substance C2. The reaction creates CB and A. If C2 was in excess during the second reaction, then how many moles of CB were produced?
2.43 moles 3.82 moles 4.38 moles 7.02 moles None of these
15. How many grams is 0.25 moles of table salt (NaCl?)
58.44 grams 14.61 grams 14.6 grams 58 grams 15 grams
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