Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
d 1. Which branch of chemistry deals with the mass relationships of elements in compounds and the mass relationships among reactants and products in chemical reactions?
a. | qualitative analysis | c. | chemical kinetics |
b. | entropy | d. | stoichiometry |
b 2. What is the study of the mass relationships of elements in compounds?
a. | reaction stoichiometry | c. | percent yield |
b. | composition stoichiometry | d. | Avogadro's principle |
___c_ 3. Which of the following would be investigated in reaction stoichiometry?
a. | the masses of hydrogen and oxygen in water |
b. | the amount of energy released in chemical reactions |
c. | the mass of potassium required to produce a known mass of potassium chloride |
d. | the types of bonds that break and form when acids react with metals |
a 4. A balanced chemical equation allows one to determine the
a. | mole ratio of any two substances in the reaction. |
b. | energy released in the reaction. |
c. | electron configuration of all elements in the reaction. |
d. | mechanism involved in the reaction. |
b 5. The coefficients in a chemical equation represent the
a. | masses, in grams, of all reactants and products. |
b. | relative numbers of moles of reactants and products. |
c. | number of atoms in each compound in a reaction. |
d. | number of valence electrons involved in the reaction. |
d 6. Each of the four types of reaction stoichiometry problems requires using a
a. | table of bond energies. | c. | Lewis structure. |
b. | chart of electron configurations. | d. | mole ratio. |
D 7. In the reaction 2Al2O3 → 4Al + 3O2, what is the mole ratio of aluminum to oxygen?
A__ 8. In the reaction 2H2 + O2 → 2H2O, what is the mole ratio of oxygen to water?
B 9. In the reaction Zn + H2SO4 → ZnSO4 + H2, what is the mole ratio of zinc to sulfuric acid?
C__ 10. In the reaction N2 + 3H2 → 2NH3, what is the mole ratio of hydrogen to ammonia?
A__ 11. For the reaction CH4 + 2O2 → 2H2O + CO2, calculate the percent yield of carbon dioxide if 1000. g of methane react with excess oxygen to produce 2300. g of carbon dioxide.
a. | 83.88% | c. | 92.76% |
b. | 89.14% | d. | 96.78% |
___C_ 12. For the reaction 2Na + 2H2O → 2NaOH + H2, calculate the percent yield if 80. g of water react with excess sodium to produce 4.14 g of hydrogen.
D 13. Which reactant controls the amount of product formed in a chemical reaction?
a. | excess reactant | c. | composition reactant |
b. | mole ratio | d. | limiting reactant |
B 14. A chemical reaction involving substances A and B stops when B is completely used. B is the
a. | excess reactant. | c. | primary reactant. |
b. | limiting reactant. | d. | primary product. |
___B_ 15. What is the ratio of the actual yield to the theoretical yield, multiplied by 100%?
a. | mole ratio | c. | Avogadro yield |
b. | percent yield | d. | excess yield |
A 16. What is the measured amount of a product obtained from a chemical reaction?
a. | mole ratio | c. | theoretical yield |
b. | percent yield | d. | actual yield |
___D_ 17. What is the maximum possible amount of product obtained in a chemical reaction?
a. | theoretical yield | c. | mole ratio |
b. | percent yield | d. | actual yield |
C 18. A chemist interested in the efficiency of a chemical reaction would calculate the
a. | mole ratio. | c. | percent yield. |
b. | energy released. | d. | rate of reaction. |
Problem
19. What mass in grams of sodium hydroxide is produced if 20.0 g of sodium metal reacts with excess water according to the chemical equation 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)?
34.8g
20. What mass in grams of hydrogen gas is produced if 20.0 mol of Zn are added to excess hydrochloric acid according to the equation Zn(s) +2HCl(aq) → ZnCl2(aq) + H2(g)
40.4g
Knowt
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