Name: Class: _ Date: _ Chpt 12 review Multiple Choice Identify the choice that best completes the statement or answers the question. 1. What is conserved in the reaction shown below? H 2 + Cl 2 2HCl a. mass only b. mass and moles only c. mass, moles, and molecules only d. mass, moles, molecules, and volume 2. What is the first step in most stoichiometry problems? a. add the coefficients of the reagents b. convert given quantities to moles c. convert given quantities to volumes d. convert given quantities to masses 3. In the reaction 2CO + O 2 2CO 2, what is the ratio of moles of oxygen used to moles of CO 2 produced? a. 1:1 b. 2:1 c. 1:2 d. 2:2 4. Which of the following is true about the reaction shown below? C 5 (l) + 8O 2 5CO 2 + 6H 2 O a. 9 moles of reactants chemically change into 11 moles of product. b. 9 grams of reactants chemically change into 11 grams of product. c. 9 liters of reactants chemically change into 11 liters of product. d. 9 atoms of reactants chemically change into 11 atoms of product. 5. Which of the following is an INCORRECT interpretation of the balanced equation shown below? 2S + 3O 2 2SO 3 a. 2 atoms S + 3 molecules O 2 2 molecules SO 3 b. 2 g S + 3 g O 2 2 g SO 3 c. 2 mol S + 3 mol O 2 2 mol SO 3 d. 5 mol of reactants 2 mol of products 6. How many moles of aluminum are needed to react completely with 1.2 mol of FeO? 2Al + 3FeO 3Fe + Al 2 O 3 a. 1.2 mol b. 0.8 mol c. 1.6 mol d. 2.4 mol 1
Name: 7. Calculate the number of moles of Al 2 O 3 that are produced when 0.60 mol of Fe is produced in the following reaction. 2Al + 3FeO 3Fe + Al 2 O 3 a. 0.20 mol b. 0.40 mol c. 0.60 mol d. 0.90 mol 8. How many moles of glucose, C 6, can be "burned" biologically when 10.0 mol of oxygen is available? C 6 + 6O 2 6CO 2 + 6H 2 O(l) a. 0.938 mol b. 1.67 mol c. 53.3 mol d. 60.0 mol 9. Hydrogen gas can be produced by reacting aluminum with sulfuric acid. How many moles of sulfuric acid are needed to completely react with 15.0 mol of aluminum? 2Al + 3H 2 SO 4 (aq) Al 2 (SO 4 ) 3 (aq) + 3H 2 a. 0.100 mol b. 10.0 mol c. 15.0 mol d. 22.5 mol 10. When iron rusts in air, iron(iii) oxide is produced. How many moles of oxygen react with 2.4 mol of iron in the rusting reaction? 4Fe + 3O 2 2Fe2O 3 a. 1.2 mol b. 1.8 mol c. 2.4 mol d. 3.2 mol 11. At STP, how many liters of oxygen are required to react completely with 3.6 liters of hydrogen to form water? 2H 2 + O 2 2H 2 O a. 1.8 L b. 3.6 L c. 2.0 L d. 2.4 L 12. Which type of stoichiometric calculation does not require the use of the molar mass? a. mass-mass problems b. mass-volume problems c. mass-particle problems d. volume-volume problems 2
Name: 13. Aluminum reacts with sulfuric acid to produce aluminum sulfate and hydrogen gas. How many grams of aluminum sulfate would be formed if 250 g H 2 SO 4 completely reacted with aluminum? 2Al + 3H 2 SO 4 (aq) Al 2 (SO 4 ) 3 (aq) + 3H 2 a. 0.85 g b. 290 g c. 450 g d. 870 g 14. How many liters of hydrogen gas are needed to react with CS 2 to produce 2.50 L of CH 4 at STP? 4H 2 +CS 2 (l) CH 4 + 2H 2 S a. 2.50 L b. 5.00 L c. 7.50 L d. 10.0 L 15. Which conversion factor do you use first to calculate the number of grams of CO 2 produced by the reaction of 50.6 g of CH 4 with O 2? The equation for the complete combustion of methane is: CH 4 + 2O 2 CO 2 +2H 2 O(l) a. 1 mol CH 4 /16.0 g CH 4 b. 2 mol O 2 /1 mol CO 2 c. 16.0 g CH 4 /1 mol CO 4 d. 44.0 g CO 2 /2 mol CO 2 16. How many liters of NH 3 are needed to react completely with 30.0 L of NO (at STP)? 4NH 3 + 6NO 5N 2 + 6H 2 O a. 5.0 L b. 20.0 L c. 7.5 L d. 120.0 L 17. Glucose, C 6, is a good source of food energy. When it reacts with oxygen, carbon dioxide and water are formed. How many liters of CO 2 are produced when 126 g of glucose completely react with oxygen? C 6 + 6O 2 6CO 2 + 6H 2 O(l) + 673 kcal a. 4.21 L b. 5.33 L c. 15.7 L d. 94.1 L 3
Name: 18. Calcium oxide, or lime, is produced by the thermal decomposition of limestone in the reaction CaCO 3 Δ CaO + CO 2. What mass of lime can be produced from 1.5 10 3 kg of limestone? a. 8.4 10 5 kg b. 8.4 10 2 kg c. 8.4 kg d. none of the above 19. How many grams of chromium are needed to react with an excess of CuSO 4 to produce 27.0 g Cu? 2Cr + 3CuSO 4 (aq) Cr 2 (SO 4 ) 3 (aq) + 3Cu a. 14.7 g b. 18.0 g c. 33.2 g d. 81.5 g 20. How many grams of beryllium are needed to produce 36.0 g of hydrogen? (Assume an excess of water.) Be + 2H 2 O(l) Be(OH) 2 (aq) + H 2 a. 4.00 g b. 36.0 g c. 162 g d. 324 g 21. What is the maximum number of grams of PH 3 that can be formed when 6.2 g of phosphorus reacts with 4.0 g of hydrogen to form PH 3? P 4 + 6H 2 4PH 3 a. 0.43 g b. 6.8 g c. 270 g d. 45 g 22. Methane and hydrogen sulfide form when hydrogen reacts with carbon disulfide. Identify the excess reagent and calculate how much remains after 36 L of H 2 reacts with 12 L of CS 2. 4H 2 + CS 2 CH 4 + 2H 2 S a. 3 L CS 2 b. 6 L CS 2 c. 9 L CS 2 d. 12 L H 2 4
Name: 23. Which of the following would be the limiting reagent in the reaction shown below? 2H 2 + O 2 2H 2 O a. 50 molecules of H 2 b. 50 molecules of O 2 c. Neither a nor b is limiting. d. Both a and b are considered limiting reagents. 24. Which of the following is true about "yield"? a. The value of the actual yield must be given in order for the percent yield to be calculated. b. The theoretical yield is always the same as the actual yield. c. The percent yield may be different from the theoretical yield because reactions do not always go to completion. d. The actual yield may be different from the theoretical yield because insufficient limiting reagent was used. 25. Hydrogen gas is produced when zinc reacts with hydrochloric acid. If the actual yield of this reaction is 85%, how many grams of zinc are needed to produce 112 L of H 2 at STP? Zn + 2HCl(aq) ZnCl 2 + H 2 a. 95 g b. 180 g c. 280 g d. 380 g 5
Chpt 12 review Answer Section MULTIPLE CHOICE 1. ANS: D PTS: 1 DIF: L2 REF: p. 389 OBJ: 12.1.2 Describe the quantities you can use to interpret a balanced chemical equation. 2. ANS: B PTS: 1 DIF: L1 REF: p. 394 BLM: knowledge 3. ANS: C PTS: 1 DIF: L2 REF: p. 390 4. ANS: A PTS: 1 DIF: L2 REF: p. 386 p. 387 OBJ: 12.1.2 Describe the quantities you can use to interpret a balanced chemical equation. 5. ANS: B PTS: 1 DIF: L2 REF: p. 386 p. 387 OBJ: 12.1.2 Describe the quantities you can use to interpret a balanced chemical equation. 6. ANS: B PTS: 1 DIF: L2 REF: p. 390 p. 391 7. ANS: A PTS: 1 DIF: L2 REF: p. 390 p. 391 8. ANS: B PTS: 1 DIF: L2 REF: p. 390 p. 391 9. ANS: D PTS: 1 DIF: L2 REF: p. 390 p. 391 10. ANS: B PTS: 1 DIF: L2 REF: p. 390 p. 391 11. ANS: A PTS: 1 DIF: L2 REF: p. 394 p. 396 12. ANS: D PTS: 1 DIF: L2 REF: p. 396 BLM: comprehension 13. ANS: B PTS: 1 DIF: L2 REF: p. 392 p. 393 14. ANS: D PTS: 1 DIF: L2 REF: p. 396 1
15. ANS: A PTS: 1 DIF: L2 REF: p. 392 16. ANS: B PTS: 1 DIF: L2 REF: p. 396 17. ANS: D PTS: 1 DIF: L2 REF: p. 392 p. 393 18. ANS: B PTS: 1 DIF: L2 REF: p. 392 p. 393 19. ANS: A PTS: 1 DIF: L2 REF: p. 403 20. ANS: C PTS: 1 DIF: L2 REF: p. 403 21. ANS: B PTS: 1 DIF: L2 REF: p. 402 22. ANS: A PTS: 1 DIF: L2 REF: p. 401 23. ANS: B PTS: 1 DIF: L2 REF: p. 402 24. ANS: D PTS: 1 DIF: L2 REF: p. 405 OBJ: 12.3.2 Explain what the percent yield of a reaction measures. 25. ANS: D PTS: 1 DIF: L3 REF: p. 406 p. 408 OBJ: 12.3.2 Explain what the percent yield of a reaction measures. 2