1. Which response contains all the molecules below that violate the octet rule, and no others? SF 4, SiCl 4, H 2Te, AsF 5, BeI 2

Transcription

1 Chem 1100 Pre-Test Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Which response contains all the molecules below that violate the octet rule, and no others? SF 4, SiCl 4, H 2Te, AsF 5, BeI 2 a. SF 4, AsF 5, BeI 2 b. BeI 2 c. H 2Te, BeI 2 d. SF 4, SiCl 4 e. AsF 5 2. Which numbered response lists all the molecules below that exhibit resonance and none that do not? I. PF 5 II. HNO 3 III. SO 2 IV. H 2O a. I and II b. II and III c. III and IV d. I and III e. II, III, and IV 3. Which one of the following molecules has a central atom that is sp 2 hybridized? a. BeF 2 b. BCl 3 c. PCl 3 d. H 2O e. NH 3 4. Which of the following molecules has three lone pairs of electrons on the central atom? a. XeF 4 b. SF 4 c. SF 6 d. XeF 2 e. NCl 3 5. For AsF 3, the electronic geometry is and the molecular geometry is. a. tetrahedral; trigonal planar b. trigonal planar; tetrahedral c. tetrahedral; tetrahedral d. trigonal planar; trigonal planar e. trigonal planar; linear 6. Which of the following molecules has the smallest bond angle(s)? a. CH 4 b. NH 3 c. H 2O

2 d. CF 4 e. CO 2 7. Which one of the following is a nonpolar molecule with polar bonds? a. H 2O b. NH 3 c. PF 5 d. CHCl 3 e. none of these 8. Which one of the following molecules is octahedral? a. BeCl 2 b. SeF 6 c. BF 3 d. PF 5 e. CF 4 9. How many sigma (σ) bonds and how many pi (π) bonds does the ethene molecule contain? a. 4 σ, 2 π b. 5 σ, 2 π c. 5 σ, 1 π d. 5 σ, 0 π e. 8 σ, 2 π 10. Which of the following molecules has an asymetric structure? a. XeF 4 b. SF 4 c. SF 6 d. XeF 2 e. BCl The overlap of the 2p atomic orbitals produces sigma molecular orbitals and pi molecular orbitals. a. 2; 3 b. 2; 4 c. 4; 2 d. 1; 2 e. 3; What is the best definition of bond order? a. A bond resulting from the occupation of a pi molecular orbital. b. The amount of energy required to break one mole of bonds. c. A bond resulting from the occupation of a sigma molecular orbital. d. The number of bonding molecular orbitals minus the number of antibonding molecular orbitals. e. Half the number of electrons in bonding molecular orbitals minus half the number of electrons in antibonding molecular orbitals. 13. Which Lewis Dot Formula below is incorrect?

3 a. b. c. d. e. 14. How many valence electrons does a phosphorus atom have? a. 2 b. 6 c. 3 d. 5 e Which of the following is the correct Lewis dot formula for H 2S? a. b. c. d. e. 16. Draw the Lewis dot formula for PCl 3. The number of unshared pairs of electrons in the outer shell of the central atom is. a. one b. two c. three d. four e. zero 17. The Lewis structure for the carbonate ion, CO 3, shows doubles bond(s), single bond(s) and lone pair(s) on the central atom. a. 3; 1; 2 b. 1; 2; 0 c. 2; 2; 1 d. 2; 1; 1 e. 2; 1; Which Lewis dot formula is incorrect?

4 a. b. c. d. e. 19. The total number of covalent bonds in the N 2 molecule is. a. one b. two c. three d. four e. zero 20. How many lone pairs of electrons are there on the Xe atom in the XeF 4 molecule? a. one b. two c. three d. four e. zero 21. Which one of the following molecules contains bonds that are the most polar? (Electronegativities: H = 2.1, Be = 1.5, B = 2.0, N = 3.0, F = 4.0, S = 2.5, Br = 2.8, I = 2.5) a. SF 6 b. BI 3 c. BeBr 2 d. NH 3 e. NF Which one of the following molecules is nonpolar? a. H 2O b. CO 2 c. CSO d. NF 3 e. NH 3

5 23. The hybridization associated with the central atom of a molecule in which all the bond angles are 180 is. a. sp b. sp 2 c. sp 3 d. sp 3 d e. sp 3 d The central atom in a molecule is bonded to 3 other atoms and has 2 lone pairs. What type of hybrid orbitals are formed by the central atom? a. sp b. sp 2 c. sp 3 d. sp 3 d e. sp 3 d The electronic geometry of the central atom in PCl 3 is. a. pyramidal b. trigonal planar c. tetrahedral d. octahedral e. trigonal bipyramidal 26. What is the coefficient for HBr when the following equation is balanced with the smallest whole number coefficients? Br 2 + H 2O HBr + HBrO 3 a. 5 b. 7 c. 8 d. 3 e Ammonium nitrate fertilizer is sometimes used as an explosive. How many moles of water can be formed from the decomposition of 13.2 moles of ammonium nitrate? 2NH 4NO 3 2N 2 + O 2 + 4H 2Ο a b c d e The thermite reaction is performed using 8.6 g Fe 2O 3 and 1.8 g powdered Al metal. Which reactant is in excess and by how much? Fe 2O Al Al 2O 3 + 2Fe a. Al; 0.3 g b. Fe 2O 3; 2.0 g c. Al; 2.1 g d. Al; 1.1 g e. Fe 2O 3; 3.3 g

6 29. What is the percent yield of elemental sulfur if 7.54 grams of sulfur are obtained from the reaction of 6.16 grams of SO 2 with an excess of H 2S? 2H 2S + SO 2 2H 2O + 3S a. 72.6% b. 40.8% c. 81.5% d. 88.4% e. 91.4% 30. What is the molarity of 850. ml of a solution containing 46.2 grams of NaBr? a M b M c M d M e M 31. Concentrated hydrochloric acid is about 12.1 M. What volume of concentrated HCl is required to produce 5500 ml of M? a. 980 ml b L c. 98 ml d L e ml 32. What volume of M HCl solution will just react with gram of Ba(OH) 2? 2HCl + Ba(OH) 2 BaCl 2 + 2H 2O a ml b ml c ml d ml e ml 33. According to the Brønsted-Lowry theory, a base is defined as. a. an electron pair acceptor b. a proton acceptor c. an electron pair donor d. a proton donor e. any species that can produce hydroxide ions in aqueous solution 34. Which one of the following is a weak acid? a. H 2SO 4 b. HClO c. HCl d. HBr e. HI 35. Consider the complete neutralization reactions between the following acid-base pairs in dilute aqueous solutions. Which one of the reactions produces insoluble salts? a. CH 3COOH + NaOH

7 b. HNO 3 + Mg(OH) 2 c. H 3PO 4 + Ca(OH) 2 d. HCl + KOH e. H 2SO 4 + Sr(OH) Which of the following reactions is the net ionic equation for the acid-base reaction between H 2CO 3 and Sr(OH) 2? a. H 2CO 3 + Sr OH SrCO 3 + 2H 2O b. H 3O + + OH 2H 2O c. 2H 3O + + Sr OH Sr H 2O d. H 2CO 3 + 2OH 2H 2O + CO 3 e. H 2CO 3 + Sr(OH) 2 2H 2O + Sr 2+ + CO If 20 ml of M H 3PO 4 solution is completely neutralized by 60.0 ml of Ca(OH) 2 solution, what is the molarity of the Ca(OH) 2 solution? a M b M c M d M e M 38. What is the oxidation number of arsenic in K 3AsO 4? a. +1 b. +2 c. +3 d. +4 e Name the molecular compound, HNO 3. a. ammonia b. nitric acid c. nitrous acid d. nitric oxide e. methane 40. Balance the following equation with the smallest whole number coefficients. Choose the answer that is the sum of the coefficients in the balanced equation. Do not forget coefficients of "one". Cr + H 2SO 4 Cr 2(SO 4) 3 + H 2 a. 7 b. 9 c. 11 d. 13 e How many moles of O 2 are required to burn completely 63.5 g of C 6H 6, according to the following equation? 2C 6H O 2 12CO 2 + 6H 2O a b c. 6.1 d

8 e Acrylonitrile, C 3H 3N, is a molecule used to produce a plastic called Orlon. How many grams of acrylonitrile could be produced by reacting 583 g of propene, C 3H 6 with excess ammonia, NH 3 and oxygen? 2C 3H 6 + 2NH 3 + 3O 2 2C 3H 3N + 6H 2O a. 368 g b g c. 462 g d. 735 g e. 583 g 43. A mixture of calcium oxide, CaO, and calcium carbonate, CaCO 3, that had a mass of g was heated until all the calcium carbonate was decomposed according to the following equation. After heating, the sample had a mass of g. Calculate the mass of CaCO 3 present in the original sample. CaCO 3 (solid) CaO (solid) + CO 2 (gas) a g b g c g d g e g 44. How many moles of carbon dioxide could be produced if 10 moles of octane, C 8H 18, are combined with 20 moles of oxygen? C 8H O 2 16CO H 2O a. 40 mol b. 8.0 mol c mol d mol e. 20 mol 45. What mass of Cu(NO 3) 2 can be prepared from the reaction of 3.65 grams of copper with 5.16 grams of HNO 3? Cu + 2HNO 3 Cu(NO 3) 2 + H 2 a g b g c g d g e g 46. Salicylic acid reacts with acetic anhydride to form aspirin, acetylsalicylic acid. If the percent yield in this reaction is 78.5%, what mass of salicylic acid is required to produce 150. g aspirin? 2 C 7H 6O 3 + C 4H 6O 3 2 C 9H 8O 4 + H 2O salicylic acid acetic anhydride aspirin a. 292 g b. 146 g c g

9 d g e. 191 g 47. The reaction of 5.0 g of CuSO 4 with excess sodium hydroxide produced 2.6 g of Cu(OH) 2. What percent yield of Cu(OH) 2 was obtained? CuSO 4 + 2NaOH Cu(OH) 2 + Na 2SO 4 a. 52% b. 61% c. 32% d. 85% e. 92% 48. What is the molarity of a barium chloride solution prepared by dissolving 2.50 g of BaCl 2 2H 2O in enough water to make 400. ml of solution? a M b M c M d M e M 49. What mass of Na 2SO 4 is required to prepare 400. ml of 1.50 M Na 2SO 4 solution? a. 213 g b g c g d g e g 50. What volume of M KOH solution contains 6.31 grams of KOH? a. 631 ml b ml c. 450 ml d ml e ml 51. Calculate the molarity of the resulting solution if 25.0 ml of 1.50 M HCl solution is diluted to 500. ml. a M b M c M d M e M 52. Calculate the molarity of the resulting solution if enough water is added to 50.0 ml of 4.20 M NaCl solution to make a solution with a volume of 2.80 L. a M b M c M d M e M 53. What mass of calcium carbonate, CaCO 3, is required to react with 100. ml of 2.00 M HCl solution? CaCO 3 + 2HCl CaCl 2 + CO 2 + H 2O

10 a g b g c g d g e g 54. What volume of M KOH solution would react completely with 25.8 ml of M HCl according to the following equation? HCl + KOH KCl + H 2O a ml b ml c ml d ml e ml 55. According to the Arrhenius theory, which of the following is an acid? a. NH 3 b. CH 4 c. HCl d. H 2 e. NaOH 56. Which one of the following is a soluble, strong base? a. CsOH b. Cu(OH) 2 c. Fe(OH) 3 d. Mn(OH) 2 e. Al(OH) Which one of the following is not a soluble, strong base? a. NaOH b. KOH c. RbOH d. CsOH e. NH 2OH 58. How many moles of HCl would react with 37.1 ml of M Sr(OH)2? a b c d e In which of the following is the oxidation number of the underlined element given incorrectly? Element / Oxidation number a. K 2Cr 2O 7 / +6 b. NaAl(OH) 4 / +3 c. HIO 4 / +5 d. (NH 4) 2SO 4 / +6

11 e. NaHSO 3 / How many ml of 0.57 M AgNO 3 will completely react with 121 ml of 0.95 M NaI? AgNO 3 + NaI AgI + NaNO 3 a ml b. 181 ml c. 202 ml d ml e ml 61. Which compound is the oxidizing agent? KOH + Cl 2 KClO 3 + KCl + H 2O a. KOH b. Cl 2 c. KClO 3 d. KCl e. H 2O 62. In the following net ionic reaction, is the oxidizing agent and is oxidized. C + H + + SO 4 CO 2 + SO 2 (acidic solution) a. H + ; CO 2 b. C; CO 2 c. SO 4 ; H + d. SO 4 ; C e. C; SO 4

12 Chem 1100 Pre-Test Answer Section MULTIPLE CHOICE 1. ANS: A PTS: 1 TOP: Writing Lewis Formulas: Limitations of the Octet Rule for Lewis Formulas 2. ANS: B PTS: 1 TOP: Resonance 3. ANS: B PTS: 1 TOP: Trigonal Planar Electronic Geometry 4. ANS: D PTS: 1 TOP: Trigonal Bipyramidal Electronic Geometry: AB5, AB4U, AB3U2, and AB2U3 5. ANS: A PTS: 1 TOP: Tetrahedral Electronic Geometry: AB3U Species 6. ANS: C PTS: 1 TOP: Tetrahedral Electronic Geometry: AB2U2 Species 7. ANS: C PTS: 1 TOP: Tetrahedral Electronic Geometry: AB3U Species 8. ANS: B PTS: 1 TOP: Octahedral Electronic Geometry: AB6, AB5U, and AB4U2 9. ANS: C PTS: 1 TOP: Compounds Containing Double or Triple Bonds 10. ANS: B PTS: 1 TOP: Trigonal Bipyramidal Electronic Geometry: AB5, AB4U, AB3U2, and AB2U3 11. ANS: B PTS: 1 TOP: Molecular Orbitals 12. ANS: E PTS: 1 TOP: Bond Order and Bond Stability 13. ANS: B PTS: 1 TOP: Lewis Dot Formulas of Atoms 14. ANS: D PTS: 1 TOP: Lewis Dot Formulas of Atoms 15. ANS: C PTS: 1 TOP: Lewis Formulas for Molecules and Polyatomic Ions 16. ANS: A PTS: 1 TOP: Writing Lewis Formulas: The Octet Rule 17. ANS: B PTS: 1 TOP: Writing Lewis Formulas: The Octet Rule 18. ANS: D PTS: 1 TOP: Writing Lewis Formulas: The Octet Rule 19. ANS: C PTS: 1 TOP: Writing Lewis Formulas: The Octet Rule 20. ANS: B PTS: 1 TOP: Writing Lewis Formulas: Limitations of the Octet Rule for Lewis Formulas 21. ANS: A PTS: 1 TOP: Polar and Nonpolar Covalent Bonds 22. ANS: B PTS: 1 TOP: Polar Molecules: The Influence of Molecular Geometry 23. ANS: A PTS: 1 TOP: Valence Bond (VB) Theory 24. ANS: D PTS: 1 TOP: Valence Bond (VB) Theory 25. ANS: C PTS: 1 TOP: Tetrahedral Electronic Geometry: AB3U Species 26. ANS: A PTS: 1 TOP: Chemical Equations 27. ANS: C PTS: 1 TOP: Calculations Based on Chemical Equations 28. ANS: E PTS: 1 TOP: The Limiting Reactant Concept 29. ANS: C PTS: 1 TOP: Percent Yields from Chemical Reactions 30. ANS: D PTS: 1 TOP: Concentrations of Solutions 31. ANS: B PTS: 1 TOP: Dilution of Solutions 32. ANS: A PTS: 1 TOP: Using Solutions in Chemical Reactions 33. ANS: B PTS: 1 TOP: The Brønsted-Lowry Theory 34. ANS: B PTS: 1 TOP: Strengths of Acids 35. ANS: C PTS: 1 TOP: Acid-Base Reactions in Aqueous Solutions 36. ANS: A PTS: 1 TOP: Acid-Base Reactions in Aqueous Solutions

13 37. ANS: E PTS: 1 TOP: Calculations for Acid-Base Titrations 38. ANS: E PTS: 1 TOP: Balancing Redox Reactions 39. ANS: B PTS: 1 TOP: Chemical Formulas 40. ANS: B PTS: 1 TOP: Chemical Equations 41. ANS: C PTS: 1 TOP: Calculations Based on Chemical Equations 42. ANS: D PTS: 1 TOP: Calculations Based on Chemical Equations 43. ANS: B PTS: 1 DIF: Harder Question TOP: Calculations Based on Chemical Equations 44. ANS: C PTS: 1 TOP: The Limiting Reactant Concept 45. ANS: E PTS: 1 TOP: The Limiting Reactant Concept 46. ANS: B PTS: 1 TOP: Percent Yields from Chemical Reactions 47. ANS: D PTS: 1 TOP: Percent Yields from Chemical Reactions 48. ANS: A PTS: 1 TOP: Concentrations of Solutions 49. ANS: D PTS: 1 TOP: Concentrations of Solutions 50. ANS: C PTS: 1 TOP: Concentrations of Solutions 51. ANS: E PTS: 1 TOP: Dilution of Solutions 52. ANS: E PTS: 1 TOP: Dilution of Solutions 53. ANS: B PTS: 1 TOP: Using Solutions in Chemical Reactions 54. ANS: C PTS: 1 TOP: Using Solutions in Chemical Reactions 55. ANS: C PTS: 1 TOP: The Arrhenius Theory 56. ANS: A PTS: 1 TOP: Acid-Base Reactions in Aqueous Solutions 57. ANS: E PTS: 1 TOP: Acid-Base Reactions in Aqueous Solutions 58. ANS: B PTS: 1 TOP: Calculations Involving Molarity 59. ANS: C PTS: 1 TOP: Balancing Redox Reactions 60. ANS: C PTS: 1 TOP: Calculations Involving Molarity 61. ANS: B PTS: 1 TOP: Adding H+, OH, or H2O to Balance Oxygen or Hydrogen 62. ANS: D PTS: 1 TOP: Adding H+, OH, or H2O to Balance Oxygen or Hydrogen