Topic: Balancing Equations. 1. Balance the following equation. What is the sum of the coefficients of the reactants and products?

Transcription

1 PHYSICAL CHEMISTRY by: SHAILENDRA KR. Classes at: - Meq. Approach SCIENCE TUTRIALS; pp. Khuda Baksh Library, Ashok Rajpath, Patna PIN PINT STUDY CIRCLE; House No. 5A/65, pp. Mahual Kothi, Alpana Market, Patna Topic: Balancing Equations 1. Balance the following equation. What is the sum of the coefficients of the reactants and products? C 7 H 16 + _ 2 _ C 2 + _ H 2 a) 24 b) 21 c) 27 d) 15 e) Balance the following equation. What is the sum of the coefficients of the reactants? C 7 H _ 2 _ C 2 + _ H 2 a) 8 b) 10 c) 9 d) 12 e) Balance the following equation. What is the sum of the coefficients of the reactants? C 12 H _ 2 _ C 2 + _ H 2 a) 12 b) 10 c) 13 d) 7 e) 9 4. Balance the following equation. What is the sum of the coefficients of the reactants and products? _ Ag + _ H 2 S + _ 2 _ Ag 2 S + _ H 2 a) 10 b) 8 c) 12 d) 14 e) Balance the following equation for the oxidation of ammonia. What is the sum of the whole number coefficients of the reactants and products? _ NH 3 + _ 2 _ N + _ H 2 a) 15 b) 12 c) 20 d) 22 e) Balance the following equation and choose the quantity which is the sum of the coefficients of the products. _ S 2 Cl 2 + _ HI _ H 2 S + _ H 2 + _ HCl + _ I 2 Page No.: 1

2 a) 7 b) 8 c) 6 d) 10 e) 9 7. Balance the following equation. What is the sum of the coefficients of the reactants and products? _ Al 4 C 3 + _ HCl _ AlCl 3 + C a) 24 b) 12 c) 20 d) 18 e) Balance the following equation. What is the sum of the coefficients of the reactants and products? _ Co + _ 2 _ Co 2 3 a) 3 b) 9 c) 7 d) 6 e) 8 9. Balance the following equation and choose the quantity which is the sum of the coefficients of the products. _ SnS 2 + _ HCl _ H 2 SnCl 6 + _ H 2 S a) 5 b) 8 c) 3 d) 6 e) Balance the following equation. What is the sum of the coefficients of the reactants and products? _ Al + _ KCl 3 _ Al _ KCl a) 18 b) 13 c) 15 d) 21 e) Balance the following equation. What is the coefficient of BrF 3 in the balanced equation? _ Se + _ BrF 5 _ Se F + _ BrF 6 3 a) 3 b) 1 c) 2 d) 4 e) Balance the following equation and choose the quantity which is the sum of the coefficients of the reactants. _ HSbCl 4 + _ H 2 S _ Sb 2 S 3 + _ HCl a) 5 b) 7 c) 8 d) 9 e) Which statement is false for the balanced equation given below? (At. wt.: S = 32.06, = 16.00). 2 S S 3 a) 32 g of 2 will react with 64 g of S 2 b) ne mole of S 2 will produce 80 g of S 3 Page No.: 2

3 c) ne mole of 2 will produce two moles of S 3 d) The reaction of 32 g of 2 will produce 2 moles of S 3 e) Two molecules of S 2 react with one molecule of Which statement is false for the balanced equation given below?(at. wt.: N = 14.01, H = 1.008). N H 2 2 NH 3 a) The reaction of 14 g of nitrogen produces 34 g of NH 3 b) The reaction of one mole of H 2 will produce 2/3 mole of NH 3 c) ne mole of N 2 will produce two moles of NH 3 d) The reaction of 3 moles of hydrogen will produce 34 g of NH 3 e) ne molecule of nitrogen requires three molecules of hydrogen 15. Which statement is false for the balanced equation given below? (At wt.: C=12.01, H=1.008,=16). 2 C 2 H C H 2 a) ne mole of C 2 H 6 will produce four moles of carbon dioxide b) The reaction of 30.0 g of C 2 H 6 will produce three moles of water c) The reaction of 30.0 g of C 2 H 6 will produce 88.0 g of carbon dioxide d) The reaction of 56.0 g of 2 will produce 44.0 g of carbon dioxide e) Two molecules of C 2 H 6 requires seven molecules of oxygen 16. Which of the following setups is correct to calculate the number of moles of C required to produce 4 moles of iron according to the following equation? Fe C 2 Fe + 3 C 2 a) 4 moles Fe x 3 moles C/2 moles Fe b) 4 moles Fe x 3 moles Fe/2 moles C c) 4 moles Fe x 2 moles C/3 moles Fe d) 4 moles Fe x 2 moles Fe/3 moles C 17. Which of the following setups is correct to calculate the number of moles of Cl 2 required to produce 7 moles of iodine according to the following equation? 3 Cl FeI 2 2 FeCl I 2 a) 7 moles I 2 x 3 moles Cl 2 /2 moles I 2 b) 7 moles I 2 x 2 moles I 2 /2 moles Cl 2 c) 7 moles I 2 x 2 moles Cl 2 /3 moles I 2 d) 7 moles I 2 x 2 moles I 2 /3 moles Cl Which of the following setups is correct to calculate the number of moles of Cl 2 required to produce 6 moles of PCl 5 according to the following equation? 10 Cl 2 + P 4 4 PCl 5 a) 6 moles PCl 3 x 10 moles Cl 2 /4 moles PCl 5 b) 6 moles PCl 3 x 4 moles PCl 5 /10 moles Cl 2 c) 6 moles PCl 3 x 4 moles Cl 2 /10 moles PCl 5 d) 6 moles PCl 3 x 10 moles PCl 5 /4 moles Cl 2 Page No.: 3

4 19. Which of the following setups is correct to calculate the number of grams of KCl 3 produce from the reaction of moles of Cl 2. (Atomic weights : K = 39.1, Cl = 35.45, = 16.00) 3 Cl KH 5 KCl + KCl H 2 a) moles Cl 2 x 1 mole KCl 3 /3 moles Cl 2 x g/1 mole KCl 3 b) moles Cl 2 x 3 mole Cl 2 /1 mole KCl 3 x g/1 mole KCl 3 c) moles Cl 2 x 1 mole KCl 3 /3 moles Cl 2 x 1 mole KCl 3 /122.6 g d) moles Cl 2 x 3 moles Cl 2 /1 mole KCl 3 x 1 mole KCl 3 /122.6 g 20. Which of the following setups is correct to calculate the number of grams of C required to produce 3.2 moles of iron according to the following equation? (Atomic weights : Fe = 55.85, C = 12.01, = 16.00) Fe C 2 Fe + 3 C 2 a) 3.2 moles Fe x 3 moles C/2 moles Fe x 28 g/1 mole C b) 3.2 moles Fe x 2 moles Fe/3 moles C x 28 g/1 mole C c) 3.2 moles Fe x 2 moles Fe/3 moles C x 1 mole C / 28 g d) 3.2 moles Fe x 3 moles C/2 moles Fe x 1 mole C / 28 g 21. Which of the following setups is correct to calculate the number of grams of N 2 produced from 5 moles of N 2 according to the following equation? (Atomic weights : N = 14.01, H = 1.008) 2 H 2 + N 2 2 Fe + N 2 a) 5 moles N 2 x 2 moles N 2 /1 mole N 2 x 32 g N 2 /1 mole N 2 b) 5 moles N 2 x 2 moles N 2 /1 mole N 2 x 1 mole N 2 /32 g N 2 c) 5 moles N 2 x 2 moles N 2 /2 moles N 2 x 1 mole N 2 /32 g N 2 d) 5 moles N 2 x 1 moles N 2 /2 moles N 2 x 32 g N 2 /1 mole N Calculate the number lof moles of H 2 2 required to produce 0.04 moles of HN 3 by the following reaction. 7 H N 2 2HN H 2 a) 0.12 b) 0.04 c) 0.07 d) 0.06 e) Calculate the number of moles of HI produced from 0.32 moles of PI 3 by the following reaction. PI H 2 H P + 3 HI 3 3 a) b) 0.22 c) 1.12 d) 0.64 e) Sodium bromide can be prepared by the following series of reactions. How many moles of NaBr can be produced from 1.00 mole of Fe? Fe + Br 2 Fe Br 2 3 FeBr 2 + Br 2 Fe 3 Br 8 Fe 3 Br Na 2 C 3 8 NaBr + 4 C 2 + Fe 3 4 Page No.: 4

5 a) 3.00 b) 1.00 c) d) e) How many moles of HCl are produced from 3.24 g of CCl 2 according to the following reaction? (Atomic weights : C = 12.00, H = 1.008, Cl = 35.45). CCl 2 + H 2 C HCl a) b) c) d) e) How many grams of Si 3 N 4 can be produced from 0.46 moles of N 2? (At wt.: Si = 28.09, N = 14.01) 3 Si + 2 N 2 Si 3 N 4 a) 16 b) 24 c) 64 d) 28 e) How many grams of carbon is required to produce moles of SiC? (Atomic weights : C = 12.0, Si = 28.09, = 16.00). Si C SiC + 2 C a) 17.8 b) 17.2 c) 16.0 d) 15.4 e) Phosgene was used in WW1 as a war gas. It reacts with water in the lungs to produce HCl which causes severe lung damage and ultimately leads to death. How many grams of HCl are produced when 11.0 g of C 2 are simultaneously formed? CCl 2 + H 2 2 HCl + C 2 a) 9.11 b) 27.3 c) 36.4 d) 0.25 e) How many grams of H 2 are produced by the reaction of mol of H 3 P 4 according to the following equation? (Atomic weights: Cr = 52.00; H = 1.008: P = 30.97; = 16.00). 2 Cr + 2 H 3 P 4 2 CrP H 2 a) b) c) 1.05 d) e) A chemist who needs 80.0 g of anhydrous copper (II) sulfate, CuS 4 has available a supply of copper (II) sulfate pentahydrate, CuS 4.5 H 2, which he could dehydrate by heating. How much of the hydrated compound must be heated to obtain 80.0 g of CuS 4? (Atomic weights: Cu = 63.55, S = 32.06, = 16.00, H = 1.008) Page No.: 5

6 a) 144 b) 112 c) 101 d) 134 e) How many grams of H 2 can be produced by reaction of 1.60 g Fe and 2.00 g HCl (Atomic weights : Fe = 55.85, Cl = 35.45, H = 1.008). Fe + 2 HCl FeCl 2 + H 2 a) b) c) d) e) Zinc metal can be obtained by the following reaction. What is the lmaximum amount of Zn that can be obtained from 75.0 g of Zn and 50.0 g of C?(At. wt.: C=12.01, =16.00, Zn=65.38). Zn + C Zn + C 2 a) 117 b) 60.3 c) 81.3 d) 125 e) How many moles of Fe(H) 3 can be produced by reacting 1.0 mole Fe 2 S 3, 2.0 mole H 2 and 3.0 mole 2? 2 Fe 2 S H Fe(H) 3 +6 S a) 1.8 b) 1.3 c) 1.7 d) 2.0 e) Reaction of 1.00 mole C with excess Cl 2 yields 96.8 g CCl 4. What is the percent yield of the reaction? (Atomic weights: C = 12.01, H = , Cl = 35.45). C + 4 Cl 2 CCl HCl a) 64.3 b) 62.9 c) 65.9 d) 59.2 e) The reaction of 11 g of N 2 with excess H 2 2 according to the following reaction yields 35 g of HN 3. What is the percent yield? (Atomic weights: N = 14.01, H = 1.008, = 16.00). 7 H 2 + N 2 2 HN H 2 a) 70% b) 81% c) 72% d) 78% e) 75% 36. The reaction of g of Fe 2 3 with excess C according to the following reaction yields 8.94 g of Fe. What is the percent yield? (Atomic weights: Fe = 55.85, C = 12.01, = 16.00). Fe C 2 Fe + 3 C a) 76% b) 80% c) 78% d) 82% e) 84% Page No.: 6

7 37. The mass of CIF 3 produced from 12.4 g of chlorine and 14.0 g of fluorine is 20.5 g. What is the percent yield? (Atomic weights: Cl = 35.45, F = 19.0). Cl F 2 2 ClF 3 a) 88.4 b) 90.3 c) 90.9 d) 89.2 e) The mass of CaF 2 that results from the reaction of 3.00 g of calcium and 2.00 g of fluorine is 4.02 g. What is the percent yield? (Atomic weights: Ca = 40.08, F = 19.00). Ca + F 2 CaF 2 a) 95.0 b) 97.8 c) 98.5 d) 96.5 e) The mass of S 2 Cl 2 formed when 6.00 g of sulfur reacts with 6.00 g of chlorine is 9.5 g. What is the percent yield? (Atomic weights: S = 32.06, Cl = 35.45). S Cl 2 4 S 2 Cl 2 a) 80.5 b) 83.1 c) 82.4 d) 81.3 e) Calculate the molarity of a solution of g of KMn 4 in 2.50 ml of solution. (Atomic weights: K = 39.09, Mn = 54.94, = 16.00). a) b) c) d) e) Calculate the molarity of a solution of g of RbS 4 in 15 ml of solution. (Atomic weights: Rb = 85.47, S = 32.06, = 16.00). a) 4.4 x 10 2 b) 6.6 x 10 3 c) 4.4 x 10 1 d) 6.6 x 10 2 e) 8.8 x Calculate the molarity of a solution of g of KCl 4 in 2.50 ml of solution. (Atomic weights: K = 39.09, Cl = 35.45, = 16.00). a) b) c) d) e) Determine the number of moles of solute present in 127 ml of M Na 2 S 4. (Atomic weights: Na = 22.99, S = 32.06, = 16.00). a) b) c) d) e) Page No.: 7

8 44. Determine the number of moles of solute present in 455 ml of 3.75 M HCl solution. (Atomic weights: Cl = 35.45, H = 1.008). a) 1.23 b) 1.71 c) 1.89 d) 1.56 e) Determine the number of moles of solute present in 255 ml of 1.25 M H 2 S 4. (Atomic weights: S = 32.06, H = 1.008, = 16.00). a) b) c) d) e) Determine the mass (g) of solute required to form ml of a 1.00 M HBr solution. (Atomic weights: H = 1.008, Br = 79.9). a) 26.3 b) 22.2 c) 29.5 d) 24.2 e) Determine the mass (g) of solute required to form ml of a M NaCN solution. (Atomic weights: Na = 22.99, C =12.01, N = 14.01). a) 2.72 b) 3.21 c) 2.51 d) 2.91 e) Determine the mass (g) of solute required to form 275 ml of a M KCl 4 solution. (Atomic weights: K = 39.9, = 16.00, Cl = 35.45). a) 8.59 b) 1.97 c) 4.21 d) 12.2 e) What volume, in ml, of a 3.89 x 10 2 M solution is required to provide 2.12 g of KBr? (Atomic weights: K = 39.10, Br = 79.90). a) 325 b) 520 c) 425 d) 458 e) What volume, in ml, of a solution is required to provide g of KMn 4? (Atomic weights: K = 39.10, Mn = 54.94, = 16.00). a) 4.12 b) 3.10 c) 2.20 d) 2.50 e) What volume, in ml, of a 0.48 solution is required to provide 9.1 g of MgCl 2? (Atomic weights: Mg = 24.30, Cl = 35.45). Page No.: 8

9 a) 160 b) 170 c) 190 d) 200 e) Sodium ion in solution can be detected at the level of 46 pg/ml. What is the molarity of this solution? (1 Pg = g) (Atomic weight: Na = 22.99) a) 2.0 x 10 8 b) 1.0 x 10 6 c) 1.0 x 10 9 d) 2.0 x 10 6 e) 2.0 x Myocrisin (Na 2 C 4 H 3 4 SAu) is used to treat rheumatoid arthritis. A patient receives an injection from a solution that contains 50.0 mg of Myocrisin, in ml. What is the molarity of myocrisin? (Atomic weights: Na = 22.99, Au = 197.0, C = 12.01, H = 1.008, = 16.00, S = 32.06). a) 5.12 x 10 4 b) 5.12 x 10 1 c) 7.56 x 10 2 d) 2.56 x 10 4 e) 2.56 x The maximum permissable amount of cadmium (Cd 2+ ) in drinking water is 0.01 mg/l. What is the molarity of such a solution? (Atomic weights: Cd = ). a) 1 x 10 8 b) 1 x 10 5 c) 9 x 10 9 d) 9 x 10 5 e) 9 x A solution is prepared by dissolving mg of oxalic acid (C 2 H 2 4 ) to make ml of solution. A ml portion is then diluted to ml. What is the molarity of the final solution? (Atomic weights: C = 12.01, H = 1.008, = 16.00). a) x 10 3 b) x 10 2 c) d) x 10 2 e) Fluoxymesterone, C 20 H 29 F 3, is an anabolic steroid. A solution is prepared by dissolving 10.0 mg of the steroid in ml of water. A 1.00 ml portion of this solution is diluted to a final volume of 1.00 L. What is the resulting molarity? (At. wt.: C = 12.01, = 16.00, F = 19.00, H = 1.008, ) a) 5.94 x 10 8 b) 2.38 x c) 1.19 x d) 1.19 x 10 7 e) 5.94 x A solution containing Ni 2+ is prepared by dissolving g of pure nickel in nitric acid and diluting to 1.00 L. A ml aliquot is then diluted to ml. What is the molarty of the final solution? (Atomic weight: Ni = 58.70) a) 5.06 x 10 4 b) 5.06 x 10 3 c) 2.53 x 10 4 d) e) Page No.: 9

10 58. How many moles of sodium hydroxide, NaH, are required to react with the hydrochloric acid in 225 ml of a M HCl solution? (Atomic weights: = 16.00, H = 1.008, Cl = 35.45, Na = 22.99) NaH (aq) + HCl (aq) NaCl (aq) + H 2 (l) a) 2.25 x 10 2 b) 4.44 x 10 1 c) 2.25 x 10 3 d) 4.44 x 10 2 e) 2.25 x What mass (g) of calcium carbonate, CaC 3, is required to react with the sulfuric acid in 375.4mL of a M soluiton of H 2 S 4? (Atomic weights: Ca = 40.08, C = 12.01, = 16.00) CaC 3 (s) + H 2 S 4 (aq) CaS 4 (s) + H 2 + C 2 a) b) c) d) e) How many moles of silver nitrate, AgN 3, are required to react with the calcium chloride in ml of a M solution of CaCl 2? 2 AgN 3 (aq) + CaCl 2 (aq) 2 AgCl (s) + Ca (N 3 ) 2 (aq) a) x 10 2 b) x 10 2 c) x 10 2 d) x 10 3 e) x What volume, in ml of M NaH is required to precipitate all of the nickel (II) from 75.0 ml of M Ni(H) 2? (Atomic weights: Ni = 58.70, Na = 22.99, = 16.00, H = 1.008). a) 15.0 b) 150 c) 225 d) 22.5 e) What volume, in ml of M HN 3 solution is needed to titrate 125 ml of a M Ca(H) 2 solution? Ca(H) HN 3 Ca(N 3 ) H 2 a) 200 b) 150 c) 100 d) 50 e) What volume, in ml of M HCl will react completely with g of Mg(H) 2? (Atomic weights: Mg = 24.3, = 16.00, H = 1.008, Cl = 35.45). Mg(H) HCl MgCl H 2 a) 48.8 b) 40.2 c) 73.6 d) 36.8 e) The lead nitrate, Pb(N 3 ) 2, in ml of a M solution reacts with all of the aluminum sulfate, Al 2 (S 4 ) 3, in ml of solution. What is the molar concentration of the Al 2 (S 4 ) 3 in the original Al 2 (S 4 ) 3 solution? 3 Pb(N 3 ) 2 (aq) + Al 2 (S 4 ) 3 (aq) 3 PbS 4 (s) + 2 Al (N 3 ) 3 (aq) Page No.: 10

11 a) x 10 2 b) x 10 2 c) x 10 2 d) x 10 2 e) x A ml sample of sulfuric acid solution from an automobile battery reacts exactly with ml of a 1.95 M solution of sodium hydroxide, NaH. What is the molar concentration of the battery acid? H 2 S 4 (aq) + 2 NaH (aq) Na 2 S 4 (aq) + 2 H 2 (l) a) 3.41 b) 4.22 c) 5.42 d) 1.70 e) A 5.00 ml sample of vinegar, which contains acetic acid (CH 3 C 2 H), was titrated with a M NaH solution. If ml of NaH solution was required to reach the end point, what was the molar concentration of acetic acid in the vinegar? a) b) c) d) e) A 5.0 g sample of blood is titrated with 3.68 ml of M K 2 Cr 2 7 to determine the percent of alcohol. What is the mass percent? (Atomic weights: C = 12.01, H = 1.008, = 16.00, Cr = 52.00, K = 39.10). 16 H Cr C 2 H 5 H 4 Cr H C 2 a) 0.18 b) 0.27 c) d) e) Chloromycetin (C 11 H 12 5 N 2 Cl 2 ) can be chemically converted into Cl ions which is precipitated as AgCl. A 745 mg sample of an ointment yields 2.54 mg of AgCl. What is the weight percent of chloromycetin in the ointment? (Atomic weights: C = 12.01, H = 1.008, = 16.00, N = 14.01, Cl = 35.45, Ag = ). a) 0.65 b) 2.12 c) 4.24 d) 1.54 e) An ore of iron is converted into a solution of Fe 2+ and is titrated with KMn 4 solution. If a g sample of ore requires ml of M KMn 4, what is the percent of iron in the iron ore? (Atomic weights: Fe = 55.85, Mn = 54.94, = 16.00, H = 1.008) a) 17.7 b) 86.2 c) 91.6 d) 31.0 e) 93.2 Page No.: 11

12 A N S W E R S 1. c 16. a 31. b 46. e 61. c 2. c 17. a 32. b 47. e 62. c 3. c 18. a 33. b 48. e 63. c 4. e 19. a 34. b 49. d 64. a 5. e 20. a 35. b 50. d 65. a 6. e 21. a 36. b 51. d 66. a 7. c 22. e 37. b 52. e 67. d 8. c 23. e 38. b 53. e 68. d 9. c 24. e 39. b 54. e 69. d 10. a 25. e 40. e 55. a 11. a 26. e 41. e 56. a 12. a 27. e 42. e 57. a 13. a 28. e 43. b 58. a 14. a 29. e 44. b 59. a 15. a 30. e 45. b 60. a Page No.: 12