Chem 1411 Exam 2. Student:

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1 Chem 1411 Exam 2 Student: 1. Select the correct set of products for the following reaction. Ba(OH (aq) + HNO 3 (aq) A.BaN 2 + H 2 B.Ba(NO 3 (aq) + H 2 C.Ba + H 2 (g) + NO 2 (g) D.Ba 2 O + NO 2 (g) + H 2 E.No reaction occurs 2. Potassium chloride is used as a substitute for sodium chloride for individuals with high blood pressure. Identify the limiting reactant and determine the mass of the excess reactant remaining when 7.00 g of chlorine gas reacts with 5.00 g of potassium to form potassium chloride. A.Potassium is the limiting reactant; 2.47 g of chlorine remain. B.Potassium is the limiting reactant; 7.23 g of chlorine remain. C.Chlorine is the limiting reactant; 4.64 g of potassium remain. D.Chlorine is the limiting reactant; 2.70 g of potassium remain. E.No limiting reagent: the reactants are present in the correct stoichiometric ratio. 3. Hydroxylamine nitrate contains mass % N, 4.20 mass % H, and mass O. If its molar mass is between 94 and 98 g/mol, what is its molecular formula? A.NH 2 O 5 B.N 2 H 4 C.N 3 H 3 O 3 D.N 4 H 8 O 2 E.N 2 H 2 1

2 4. In the following reaction, what ions, if any, are spectator ions? Pb(NO 3 (aq) + 2NaCl(aq) PbCl 2 + 2NaNO 3 (aq) A.Pb 2+ (aq), Cl - (aq) B.Na + (aq), NO 3 - (aq) C.Pb 2+ (aq), NO 3 - (aq) D.Na + (aq), Cl - (aq) E.There are no spectator ions 5. How many moles of ions are released when 0.27 mol of cobalt(ii) chloride, CoCl 2, is dissolved in water? A.0.81 mol B.0.54 mol C.0.27 mol D.0.18 mol E mol 6. Aluminum will react with bromine to form aluminum bromide (used as an acid catalyst in organic synthesis). Al + Br 2 (l) Al 2 Br 6 [unbalanced] How many moles of Al are needed to form 2.43 mol of Al 2 Br 6? A.7.29 mol B.4.86 mol C.2.43 mol D.1.62 mol E.1.22 mol 7. Calculate the number of moles in 17.8 g of the antacid magnesium hydroxide, Mg(OH. A.3.28 mol B.2.32 mol C mol D mol E mol 2

3 8. In a blast furnace, elemental iron is produced from a mixture of coke (C), iron ore (Fe 3 ) and other reactants. An important reaction sequence is 2C + O 2 (g) 2CO(g) Fe 3 + 4CO(g) 3Fe(l) + 4CO 2 (g) How many moles of iron can be formed in this sequence when 1.00 mol of carbon, as coke, is consumed? A.6.00 mol Fe B.3.00 mol Fe C.1.33 mol Fe D.1.25 mol Fe E mol Fe 9. Balance the following equation: Ca 3 (P + SiO 2 + C CaSiO 3 + CO(g) + P 4 A.Ca 3 (P + 3SiO 2 + 8C 3CaSiO 3 + 8CO(g) + P 4 B.Ca 3 (P + 3SiO C 3CaSiO CO(g) + P 4 C.Ca 3 (P + 3SiO 2 + 8C 3CaSiO 3 + 8CO(g) + 2P 4 D.2Ca 3 (P + 6SiO C 6CaSiO CO(g) + P 4 E.2Ca 3 (P + 6SiO C 6CaSiO CO(g) + 4P Household sugar, sucrose, has the molecular formula C 12 H 22 O 11. What is the % of carbon in sucrose, by mass? A.26.7 % B.33.3 % C.41.4 % D.42.1 % E.52.8 % 3

4 11. Tetraphosphorus hexaoxide ( = g/mol) is formed by the reaction of phosphorus with oxygen gas. P 4 + 3O 2 (g) P 4 O 6 If a mixture of 75.3 g of phosphorus and 38.7 g of oxygen produce 43.3 g of P 4 O 6, what is the percent yield for the reaction? A.57.5% B.48.8% C.38.0% D.32.4% E.16.3% 12. Select the classification for the following reaction. Na 2 O + H 2 2NaOH(aq) A.combination B.decomposition C.displacement D.acid-base E.precipitation 13. Calculate the mass in grams of molecules of CBr 4. A g B g C.7.21 g D.12.7 g E.46.0 g 14. Calculate the molar mass of rubidium carbonate, Rb 2 CO 3. A g/mol B g/mol C g/mol D g/mol E g/mol 4

5 15. Terephthalic acid, used in the production of polyester fibers and films, is composed of carbon, hydrogen, and oxygen. When g of terephthalic acid was subjected to combustion analysis it produced g CO 2 and g H 2 O. What is its empirical formula? A.C 2 H 3 B.C 3 H 4 O 2 C.C 4 H 3 O 2 D.C 5 H 12 E.C 2 H 2 O 16. Select the precipitate that forms when aqueous lead(ii) nitrate reacts with aqueous sodium sulfate. A.NaNO 3 B.Na 2 NO 3 C.PbS D.Pb 2 S E.PbS 17. Sodium bromate is used in a mixture which dissolves gold from its ores. Calculate the mass in grams of 4.68 mol of sodium bromate. A.706 g B.482 g C.383 g D.32.2 g E g 18. Select the net ionic equation for the reaction between sodium chloride and mercury(i) nitrate. 2NaCl(aq) + Hg 2 (NO 3 (aq) NaNO 3 (aq) + Hg 2 Cl 2 A.Na + (aq) + NO 3 - (aq) NaNO3 (aq) B.Hg 2 2+ (aq) + 2Cl - (aq) Hg2 Cl 2 C.NaCl(aq) Na + (aq) + Cl - (aq) D.Hg 2 (NO 3 (aq) Hg 2 2+ (aq) + 2NO3 - (aq) E.Hg 2 2+ (aq) Hg2 5

6 19. Hydroxylamine nitrate contains mass % N, 4.20 mass % H, and mass % O. Determine its empirical formula. A.HNO B.H 2 NO 2 C.HN 6 O 16 D.HN 16 O 7 E.H 2 NO Which of the following solutions will be the poorest conductor of electrical current? A.sucrose, C 12 H 22 O 11 (aq) B.sodium chloride, NaCl(aq) C.potassium nitrate, KNO 3 (aq) D.lithium hydroxide, LiOH(aq) E.sulfuric acid, H 2 S (aq) 21. Copper(II) sulfate pentahydrate, CuS 5H 2 O, is used as a fungicide and algicide. Calculate the mass of oxygen in mol of CuS 5H 2 O. A g B g C g D g E g 22. Ammonia, an important source of fixed nitrogen that can be metabolized by plants, is produced using the Haber process in which nitrogen and hydrogen combine. N 2 (g) + 3H 2 (g) 2NH 3 (g) How many grams of nitrogen are needed to produce 325 grams of ammonia? A.1070 g B.535 g C.267 g D.178 g E.108 g 6

7 23. A standard solution of M NaOH was used to determine the concentration of a hydrochloric acid solution. If ml of NaOH is needed to neutralize ml of the acid, what is the molar concentration of the acid? A M B M C.1.13 M D.2.26 M E.2.43 M 24. Calculate the number of oxygen atoms in g of sodium sulfate, Na 2 S. A O atoms B O atoms C O atoms D O atoms E O atoms 25. Which of the following is a strong acid? A.H 3 P B.HNO 3 C.HF D.CH 3 COOH E.H 2 O 26. Gadolinium oxide, a colorless powder which absorbs carbon dioxide from the air, contains mass % Gd. Determine its empirical formula. A.Gd 2 O 3 B.Gd 3 O 2 C.Gd 3 D.Gd 4 O 3 E.GdO 7

8 27. Potassium chloride, KCl, sodium sulfate, Na 2 S, glucose, C 6 H 12 O 6, carbon dioxide, CO 2 and ammonium phosphate, (NH 4 ) 3 P, are soluble in water. Which one produces the largest number of dissolved particles per mole of dissolved solute? A.KCl B.Na 2 S C.C 6 H 12 O 6 D.CO 2 E.(NH 4 ) 3 P 28. How many milliliters of 1.58 M HCl are needed to react completely with 23.2 g of NaHCO 3 ( = g/mol)? HCl(aq) + NaHCO 3 NaCl + H 2 + CO 2 (g) A.638 ml B.572 ml C.536 ml D.276 ml E.175 ml 29. Sulfur dioxide reacts with chlorine to produce thionyl chloride (used as a drying agent for inorganic halides) and dichlorine oxide (used as a bleach for wood, pulp and textiles). SO 2 (g) + 2Cl 2 (g) SOCl 2 (g) + Cl 2 O(g) If mol of Cl 2 reacts with excess SO 2, how many moles of Cl 2 O are formed? A mol B mol C mol D mol E mol 8

9 30. Phosphine, an extremely poisonous and highly reactive gas, will react with oxygen to form tetraphosphorus decaoxide and water. PH 3 (g) + O 2 (g) P 4 O 10 + H 2 O(g) [unbalanced] Calculate the mass of P 4 O 10 formed when 225 g of PH 3 reacts with excess oxygen. A.1880 g B.940. g C.900. g D.470 g E.56.3 g 31. Sodium chlorate is used as an oxidizer in the manufacture of dyes, explosives and matches. Calculate the mass of solute needed to prepare L of M NaClO 3 ( = g/mol). A.419 g B.169 g C g D g E g 32. Balance the following equation: UO 2 + HF(l) UF 4 + H 2 A.UO 2 + 2HF(l) UF 4 + H 2 B.UO 2 + 4HF(l) UF 4 + 2H 2 C.UO 2 + H 4 F 4 (l) UF 4 + H 4 O 2 (l) D.UO 2 + 4HF(l) UF 4 + 4H 2 E.UO 2 + 8HF(l) 2UF 4 + 4H When 2.61 g of solid Na 2 CO 3 is dissolved in sufficient water to make 250 ml of solution, the concentration of Na 2 CO 3 is: A M B.10.4 M C M D M E M 9

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11 Chem 1411 Exam 2 Key 1. (p. 145) B 2. (p. 110) A 3. (p. 96) B 4. (p. 141) B 5. (p. 137) A 6. (p. 106) B 7. (p. 90) D 8. (p. 109) E 9. (p. 101) D 10. (p. 93) D 11. (p. 114) B 12. (p. 158) A 13. (p. 90) E 14. (p. 89) C 15. (p. 98) C 16. (p. 143) C 17. (p. 90) A 18. (p. 143) B 19. (p. 95) B 20. (p. 138) A 21. (p. 93) B 22. (p. 106) C 23. (p. 147) C 1

12 24. (p. 90) B 25. (p. 144) B 26. (p. 95) A 27. (p. 137) E 28. (p. 120) E 29. (p. 106) C 30. (p. 106) D 31. (p. 118) C 32. (p. 101) B 33. (p. 118) D 2

13 Chem 1411 Exam 2 Summary Category # of Questions Chem Difficulty: E 15 Difficulty: H 5 Difficulty: M 13 Silberberg Stoichiometry... Silberberg The