Chemistry Atoms First 2e (2019 Edition) by Paul Flowers Klaus Theopold Richard Langley Edward J. Neth William R. Robinson Chemistry Atoms First 2e (2019 Edition) by Paul Flowers Klaus Theopold Richard Langley Edward J. Neth William R. Robinson Chemistry Atoms First 2e (2019 Edition) by Paul Flowers Klaus Theopold Richard Langley Edward J. Neth William R. Robinson Chemistry Atoms First 2e (2019 Edition) by Paul Flowers Klaus Theopold Richard Langley Edward J. Neth William R. Robinson Chemistry Atoms First 2e (2019 Edition) by Paul Flowers Klaus Theopold Richard Langley Edward J. Neth William R. Robinson
Chemistry: Atoms First 2e SENIOR CONTRIBUTING AUTHORS PAUL FLOWERS, UNIVERSITY OF NORTH CAROLINA AT PEMBROKE KLAUS THEOPOLD, UNIVERSITY OF DELAWARE RICHARD LANGLEY, STEPHEN F AUSTIN STATE UNIVERSITY EDWARD J NETH, UNIVERSITY OF CONNECTICUT WILLIAM R ROBINSON, PHD OpenStax Rice University 6100 Main Street MS-375 Houston, Texas 77005 To learn more about OpenStax, visit https://openstax.org Individual print copies and bulk orders can be purchased through our website ©2019 Rice University Textbook content produced by OpenStax is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0) Under this license, any user of this textbook or the textbook contents herein must provide proper attribution as follows: - - - - If you redistribute this textbook in a digital format (including but not limited to PDF and HTML), then you must retain on every page the following attribution: “Download for free at https://openstax.org/details/books/chemistry-atoms-first-2e.” If you 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without the prior and express written consent of Rice University PRINT BOOK ISBN-10 PRINT BOOK ISBN-13 PDF VERSION ISBN-10 PDF VERSION ISBN-13 10 1-947172-64-6 978-1-947172-64-7 1-947172-63-8 978-1-947172-63-0 OPENSTAX OpenStax provides free, peer-reviewed, openly licensed textbooks for introductory college and Advanced Placement® courses and low-cost, personalized courseware that helps students learn A nonprofit ed tech initiative based at Rice University, we’re committed to helping students access the tools they need to complete their courses and meet their educational goals RICE UNIVERSITY OpenStax, OpenStax CNX, and OpenStax Tutor are initiatives of Rice University As a leading research university with a distinctive commitment to undergraduate education, Rice University aspires to path-breaking research, unsurpassed teaching, and contributions to the betterment of our world It seeks to fulfill this mission by cultivating a diverse community of learning and discovery that produces 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courses in the free OpenStax + SE app Download it now on the App Store or get it on Google Play Table of Contents Preface Chapter 1: Essential Ideas 1.1 Chemistry in Context 1.2 Phases and Classification of Matter 1.3 Physical and Chemical Properties 1.4 Measurements 1.5 Measurement Uncertainty, Accuracy, and Precision 1.6 Mathematical Treatment of Measurement Results Chapter 2: Atoms, Molecules, and Ions 2.1 Early Ideas in Atomic Theory 2.2 Evolution of Atomic Theory 2.3 Atomic Structure and Symbolism 2.4 Chemical Formulas Chapter 3: Electronic Structure and Periodic Properties of Elements 3.1 Electromagnetic Energy 3.2 The Bohr Model 3.3 Development of Quantum Theory 3.4 Electronic Structure of Atoms (Electron Configurations) 3.5 Periodic Variations in Element Properties 3.6 The Periodic Table 3.7 Molecular and Ionic Compounds Chapter 4: Chemical Bonding and Molecular Geometry 4.1 Ionic Bonding 4.2 Covalent Bonding 4.3 Chemical Nomenclature 4.4 Lewis Symbols and Structures 4.5 Formal Charges and Resonance 4.6 Molecular Structure and Polarity Chapter 5: Advanced Theories of Bonding 5.1 Valence Bond Theory 5.2 Hybrid Atomic Orbitals 5.3 Multiple Bonds 5.4 Molecular Orbital Theory Chapter 6: Composition of Substances and Solutions 6.1 Formula Mass 6.2 Determining Empirical and Molecular Formulas 6.3 Molarity 6.4 Other Units for Solution Concentrations Chapter 7: Stoichiometry of Chemical Reactions 7.1 Writing and Balancing Chemical Equations 7.2 Classifying Chemical Reactions 7.3 Reaction Stoichiometry 7.4 Reaction Yields 7.5 Quantitative Chemical Analysis Chapter 8: Gases 8.1 Gas Pressure 8.2 Relating Pressure, Volume, Amount, and Temperature: The Ideal Gas Law 8.3 Stoichiometry of Gaseous Substances, Mixtures, and Reactions 8.4 Effusion and Diffusion of Gases 8.5 The Kinetic-Molecular Theory 10 14 25 29 36 44 67 68 73 79 87 115 116 131 135 148 158 165 169 195 196 199 205 213 223 227 263 264 269 281 284 309 310 312 320 327 341 342 348 363 368 373 397 398 407 420 433 438 8.6 Non-Ideal Gas Behavior Chapter 9: Thermochemistry 9.1 Energy Basics 9.2 Calorimetry 9.3 Enthalpy 9.4 Strengths of Ionic and Covalent Bonds Chapter 10: Liquids and Solids 10.1 Intermolecular Forces 10.2 Properties of Liquids 10.3 Phase Transitions 10.4 Phase Diagrams 10.5 The Solid State of Matter 10.6 Lattice Structures in Crystalline Solids Chapter 11: Solutions and Colloids 11.1 The Dissolution Process 11.2 Electrolytes 11.3 Solubility 11.4 Colligative Properties 11.5 Colloids Chapter 12: Thermodynamics 12.1 Spontaneity 12.2 Entropy 12.3 The Second and Third Laws of Thermodynamics 12.4 Free Energy Chapter 13: Fundamental Equilibrium Concepts 13.1 Chemical Equilibria 13.2 Equilibrium Constants 13.3 Shifting Equilibria: Le Châtelier’s Principle 13.4 Equilibrium Calculations Chapter 14: Acid-Base Equilibria 14.1 Brønsted-Lowry Acids and Bases 14.2 pH and pOH 14.3 Relative Strengths of Acids and Bases 14.4 Hydrolysis of Salts 14.5 Polyprotic Acids 14.6 Buffers 14.7 Acid-Base Titrations Chapter 15: Equilibria of Other Reaction Classes 15.1 Precipitation and Dissolution 15.2 Lewis Acids and Bases 15.3 Coupled Equilibria Chapter 16: Electrochemistry 16.1 Review of Redox Chemistry 16.2 Galvanic Cells 16.3 Electrode and Cell Potentials 16.4 Potential, Free Energy, and Equilibrium 16.5 Batteries and Fuel Cells 16.6 Corrosion 16.7 Electrolysis Chapter 17: Kinetics 17.1 Chemical Reaction Rates 17.2 Factors Affecting Reaction Rates This OpenStax book is available for free at http://cnx.org/content/col26488/1.3 443 461 462 472 485 499 521 522 534 540 551 558 565 599 600 604 607 618 638 657 657 661 667 671 685 686 689 698 702 729 730 733 739 754 759 762 769 789 789 805 808 827 828 831 835 841 845 852 855 871 872 877 17.3 Rate Laws 17.4 Integrated Rate Laws 17.5 Collision Theory 17.6 Reaction Mechanisms 17.7 Catalysis Chapter 18: Representative Metals, Metalloids, and Nonmetals 18.1 Periodicity 18.2 Occurrence and Preparation of the Representative Metals 18.3 Structure and General Properties of the Metalloids 18.4 Structure and General Properties of the Nonmetals 18.5 Occurrence, Preparation, and Compounds of Hydrogen 18.6 Occurrence, Preparation, and Properties of Carbonates 18.7 Occurrence, Preparation, and Properties of Nitrogen 18.8 Occurrence, Preparation, and Properties of Phosphorus 18.9 Occurrence, Preparation, and Compounds of Oxygen 18.10 Occurrence, Preparation, and Properties of Sulfur 18.11 Occurrence, Preparation, and Properties of Halogens 18.12 Occurrence, Preparation, and Properties of the Noble Gases Chapter 19: Transition Metals and Coordination Chemistry 19.1 Occurrence, Preparation, and Properties of Transition Metals and Their Compounds 19.2 Coordination Chemistry of Transition Metals 19.3 Spectroscopic and Magnetic Properties of Coordination Compounds Chapter 20: Nuclear Chemistry 20.1 Nuclear Structure and Stability 20.2 Nuclear Equations 20.3 Radioactive Decay 20.4 Transmutation and Nuclear Energy 20.5 Uses of Radioisotopes 20.6 Biological Effects of Radiation Chapter 21: Organic Chemistry 21.1 Hydrocarbons 21.2 Alcohols and Ethers 21.3 Aldehydes, Ketones, Carboxylic Acids, and Esters 21.4 Amines and Amides Appendix A: The Periodic Table Appendix B: Essential Mathematics Appendix C: Units and Conversion Factors Appendix D: Fundamental Physical Constants Appendix E: Water Properties Appendix F: Composition of Commercial Acids and Bases Appendix G: Standard Thermodynamic Properties for Selected Substances Appendix H: Ionization Constants of Weak Acids Appendix I: Ionization Constants of Weak Bases Appendix J: Solubility Products Appendix K: Formation Constants for Complex Ions Appendix L: Standard Electrode (Half-Cell) Potentials Appendix M: Half-Lives for Several Radioactive Isotopes Index 880 887 898 904 908 939 940 950 953 962 970 977 979 984 986 1001 1003 1009 1027 1027 1042 1057 1075 1076 1083 1086 1097 1112 1117 1137 1138 1156 1160 1166 1187 1189 1197 1199 1201 1207 1209 1223 1227 1229 1233 1235 1241 1311 This OpenStax book is available for free at http://cnx.org/content/col26488/1.3 248 Chapter | Chemical Bonding and Molecular Geometry 15 From its position in the periodic table, determine which atom in each pair is more electronegative: (a) Br or Cl (b) N or O (c) S or O (d) P or S (e) Si or N (f) Ba or P (g) N or K 16 From its position in the periodic table, determine which atom in each pair is more electronegative: (a) N or P (b) N or Ge (c) S or F (d) Cl or S (e) H or C (f) Se or P (g) C or Si 17 From their positions in the periodic table, arrange the atoms in each of the following series in order of increasing electronegativity: (a) C, F, H, N, O (b) Br, Cl, F, H, I (c) F, H, O, P, S (d) Al, H, Na, O, P (e) Ba, H, N, O, As 18 From their positions in the periodic table, arrange the atoms in each of the following series in order of increasing electronegativity: (a) As, H, N, P, Sb (b) Cl, H, P, S, Si (c) Br, Cl, Ge, H, Sr (d) Ca, H, K, N, Si (e) Cl, Cs, Ge, H, Sr 19 Which atoms can bond to sulfur so as to produce a positive partial charge on the sulfur atom? 20 Which is the most polar bond? (a) C–C (b) C–H (c) N–H (d) O–H (e) Se–H This OpenStax book is available for free at http://cnx.org/content/col26488/1.3 Chapter | Chemical Bonding and Molecular Geometry 21 Identify the more polar bond in each of the following pairs of bonds: (a) HF or HCl (b) NO or CO (c) SH or OH (d) PCl or SCl (e) CH or NH (f) SO or PO (g) CN or NN 22 Which of the following molecules or ions contain polar bonds? (a) O3 (b) S8 (c) O 2− (d) NO − (e) CO2 (f) H2S (g) BH − 4.3 Chemical Nomenclature 23 Name the following compounds: (a) CsCl (b) BaO (c) K2S (d) BeCl2 (e) HBr (f) AlF3 24 Name the following compounds: (a) NaF (b) Rb2O (c) BCl3 (d) H2Se (e) P4O6 (f) ICl3 249 250 25 Write the formulas of the following compounds: (a) rubidium bromide (b) magnesium selenide (c) sodium oxide (d) calcium chloride (e) hydrogen fluoride (f) gallium phosphide (g) aluminum bromide (h) ammonium sulfate 26 Write the formulas of the following compounds: (a) lithium carbonate (b) sodium perchlorate (c) barium hydroxide (d) ammonium carbonate (e) sulfuric acid (f) calcium acetate (g) magnesium phosphate (h) sodium sulfite 27 Write the formulas of the following compounds: (a) chlorine dioxide (b) dinitrogen tetraoxide (c) potassium phosphide (d) silver(I) sulfide (e) aluminum fluoride trihydrate (f) silicon dioxide 28 Write the formulas of the following compounds: (a) barium chloride (b) magnesium nitride (c) sulfur dioxide (d) nitrogen trichloride (e) dinitrogen trioxide (f) tin(IV) chloride This OpenStax book is available for free at http://cnx.org/content/col26488/1.3 Chapter | Chemical Bonding and Molecular Geometry Chapter | Chemical Bonding and Molecular Geometry 29 Each of the following compounds contains a metal that can exhibit more than one ionic charge Name these compounds: (a) Cr2O3 (b) FeCl2 (c) CrO3 (d) TiCl4 (e) CoCl2∙6H2O (f) MoS2 30 Each of the following compounds contains a metal that can exhibit more than one ionic charge Name these compounds: (a) NiCO3 (b) MoO3 (c) Co(NO3)2 (d) V2O5 (e) MnO2 (f) Fe2O3 31 The following ionic compounds are found in common household products Write the formulas for each compound: (a) potassium phosphate (b) copper(II) sulfate (c) calcium chloride (d) titanium dioxide (e) ammonium nitrate (f) sodium bisulfate (the common name for sodium hydrogen sulfate) 32 The following ionic compounds are found in common household products Name each of the compounds: (a) Ca(H2PO4)2 (b) FeSO4 (c) CaCO3 (d) MgO (e) NaNO2 (f) KI 33 What are the IUPAC names of the following compounds? (a) manganese dioxide (b) mercurous chloride (Hg2Cl2) (c) ferric nitrate [Fe(NO3)3] (d) titanium tetrachloride (e) cupric bromide (CuBr2) 251 252 Chapter | Chemical Bonding and Molecular Geometry 4.4 Lewis Symbols and Structures 34 Write the Lewis symbols for each of the following ions: (a) As3– (b) I– (c) Be2+ (d) O2– (e) Ga3+ (f) Li+ (g) N3– 35 Many monatomic ions are found in seawater, including the ions formed from the following list of elements Write the Lewis symbols for the monatomic ions formed from the following elements: (a) Cl (b) Na (c) Mg (d) Ca (e) K (f) Br (g) Sr (h) F 36 Write the Lewis symbols of the ions in each of the following ionic compounds and the Lewis symbols of the atom from which they are formed: (a) MgS (b) Al2O3 (c) GaCl3 (d) K2O (e) Li3N (f) KF This OpenStax book is available for free at http://cnx.org/content/col26488/1.3 Chapter | Chemical Bonding and Molecular Geometry 253 37 In the Lewis structures listed here, M and X represent various elements in the third period of the periodic table Write the formula of each compound using the chemical symbols of each element: (a) (b) (c) (d) 38 Write the Lewis structure for the diatomic molecule P2, an unstable form of phosphorus found in hightemperature phosphorus vapor 39 Write Lewis structures for the following: (a) H2 (b) HBr (c) PCl3 (d) SF2 (e) H2CCH2 (f) HNNH (g) H2CNH (h) NO– (i) N2 (j) CO (k) CN– 254 Chapter | Chemical Bonding and Molecular Geometry 40 Write Lewis structures for the following: (a) O2 (b) H2CO (c) AsF3 (d) ClNO (e) SiCl4 (f) H3O+ (g) NH + (h) BF − (i) HCCH (j) ClCN (k) C 2+ 41 Write Lewis structures for the following: (a) ClF3 (b) PCl5 (c) BF3 (d) PF − 42 Write Lewis structures for the following: (a) SeF6 (b) XeF4 (c) SeCl + (d) Cl2BBCl2 (contains a B–B bond) 43 Write Lewis structures for: (a) PO 3− (b) ICl − (c) SO 2− (d) HONO 44 Correct the following statement: “The bonds in solid PbCl2 are ionic; the bond in a HCl molecule is covalent Thus, all of the valence electrons in PbCl2 are located on the Cl– ions, and all of the valence electrons in a HCl molecule are shared between the H and Cl atoms.” 45 Write Lewis structures for the following molecules or ions: (a) SbH3 (b) XeF2 (c) Se8 (a cyclic molecule with a ring of eight Se atoms) 46 Methanol, H3COH, is used as the fuel in some race cars Ethanol, C2H5OH, is used extensively as motor fuel in Brazil Both methanol and ethanol produce CO2 and H2O when they burn Write the chemical equations for these combustion reactions using Lewis structures instead of chemical formulas This OpenStax book is available for free at http://cnx.org/content/col26488/1.3 Chapter | Chemical Bonding and Molecular Geometry 255 47 Many planets in our solar system contain organic chemicals including methane (CH4) and traces of ethylene (C2H4), ethane (C2H6), propyne (H3CCCH), and diacetylene (HCCCCH) Write the Lewis structures for each of these molecules 48 Carbon tetrachloride was formerly used in fire extinguishers for electrical fires It is no longer used for this purpose because of the formation of the toxic gas phosgene, Cl2CO Write the Lewis structures for carbon tetrachloride and phosgene 49 Identify the atoms that correspond to each of the following electron configurations Then, write the Lewis symbol for the common ion formed from each atom: (a) 1s22s22p5 (b) 1s22s22p63s2 (c) 1s22s22p63s23p64s23d10 (d) 1s22s22p63s23p64s23d104p4 (e) 1s22s22p63s23p64s23d104p1 50 The arrangement of atoms in several biologically important molecules is given here Complete the Lewis structures of these molecules by adding multiple bonds and lone pairs Do not add any more atoms (a) the amino acid serine: (b) urea: (c) pyruvic acid: (d) uracil: (e) carbonic acid: 51 A compound with a molar mass of about 28 g/mol contains 85.7% carbon and 14.3% hydrogen by mass Write the Lewis structure for a molecule of the compound 256 Chapter | Chemical Bonding and Molecular Geometry 52 A compound with a molar mass of about 42 g/mol contains 85.7% carbon and 14.3% hydrogen by mass Write the Lewis structure for a molecule of the compound 53 Two arrangements of atoms are possible for a compound with a molar mass of about 45 g/mol that contains 52.2% C, 13.1% H, and 34.7% O by mass Write the Lewis structures for the two molecules 54 How are single, double, and triple bonds similar? How they differ? 4.5 Formal Charges and Resonance 55 Write resonance forms that describe the distribution of electrons in each of these molecules or ions (a) selenium dioxide, OSeO (b) nitrate ion, NO − (c) nitric acid, HNO3 (N is bonded to an OH group and two O atoms) (d) benzene, C6H6: (e) the formate ion: 56 Write resonance forms that describe the distribution of electrons in each of these molecules or ions (a) sulfur dioxide, SO2 (b) carbonate ion, CO 2− (c) hydrogen carbonate ion, HCO − (C is bonded to an OH group and two O atoms) (d) pyridine: (e) the allyl ion: 57 Write the resonance forms of ozone, O3, the component of the upper atmosphere that protects the Earth from ultraviolet radiation 58 Sodium nitrite, which has been used to preserve bacon and other meats, is an ionic compound Write the resonance forms of the nitrite ion, NO – This OpenStax book is available for free at http://cnx.org/content/col26488/1.3 Chapter | Chemical Bonding and Molecular Geometry 257 59 In terms of the bonds present, explain why acetic acid, CH3CO2H, contains two distinct types of carbon-oxygen bonds, whereas the acetate ion, formed by loss of a hydrogen ion from acetic acid, only contains one type of carbonoxygen bond The skeleton structures of these species are shown: 60 Write the Lewis structures for the following, and include resonance structures where appropriate Indicate which has the strongest carbon-oxygen bond (a) CO2 (b) CO 61 Toothpastes containing sodium hydrogen carbonate (sodium bicarbonate) and hydrogen peroxide are widely used Write Lewis structures for the hydrogen carbonate ion and hydrogen peroxide molecule, with resonance forms where appropriate 62 Determine the formal charge of each element in the following: (a) HCl (b) CF4 (c) PCl3 (d) PF5 63 Determine the formal charge of each element in the following: (a) H3O+ (b) SO 2− (c) NH3 (d) O 2− (e) H2O2 64 Calculate the formal charge of chlorine in the molecules Cl2, BeCl2, and ClF5 65 Calculate the formal charge of each element in the following compounds and ions: (a) F2CO (b) NO– (c) BF − (d) SnCl − (e) H2CCH2 (f) ClF3 (g) SeF6 (h) PO 3− 258 Chapter | Chemical Bonding and Molecular Geometry 66 Draw all possible resonance structures for each of these compounds Determine the formal charge on each atom in each of the resonance structures: (a) O3 (b) SO2 (c) NO − (d) NO − 67 Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in nitrosyl chloride: ClNO or ClON? 68 Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in hypochlorous acid: HOCl or OClH? 69 Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in sulfur dioxide: OSO or SOO? 70 Draw the structure of hydroxylamine, H3NO, and assign formal charges; look up the structure Is the actual structure consistent with the formal charges? 71 Iodine forms a series of fluorides (listed here) Write Lewis structures for each of the four compounds and determine the formal charge of the iodine atom in each molecule: (a) IF (b) IF3 (c) IF5 (d) IF7 72 Write the Lewis structure and chemical formula of the compound with a molar mass of about 70 g/mol that contains 19.7% nitrogen and 80.3% fluorine by mass, and determine the formal charge of the atoms in this compound 73 Which of the following structures would we expect for nitrous acid? Determine the formal charges: 74 Sulfuric acid is the industrial chemical produced in greatest quantity worldwide About 90 billion pounds are produced each year in the United States alone Write the Lewis structure for sulfuric acid, H2SO4, which has two oxygen atoms and two OH groups bonded to the sulfur 4.6 Molecular Structure and Polarity 75 Explain why the HOH molecule is bent, whereas the HBeH molecule is linear 76 What feature of a Lewis structure can be used to tell if a molecule’s (or ion’s) electron-pair geometry and molecular structure will be identical? 77 Explain the difference between electron-pair geometry and molecular structure 78 Why is the H–N–H angle in NH3 smaller than the H–C–H bond angle in CH4? Why is the H–N–H angle in NH + identical to the H–C–H bond angle in CH4? 79 Explain how a molecule that contains polar bonds can be nonpolar 80 As a general rule, MXn molecules (where M represents a central atom and X represents terminal atoms; n = – 5) are polar if there is one or more lone pairs of electrons on M NH3 (M = N, X = H, n = 3) is an example There are two molecular structures with lone pairs that are exceptions to this rule What are they? This OpenStax book is available for free at http://cnx.org/content/col26488/1.3 Chapter | Chemical Bonding and Molecular Geometry 81 Predict the electron pair geometry and the molecular structure of each of the following molecules or ions: (a) SF6 (b) PCl5 (c) BeH2 (d) CH + 82 Identify the electron pair geometry and the molecular structure of each of the following molecules or ions: (a) IF + (b) CF4 (c) BF3 (d) SiF − (e) BeCl2 83 What are the electron-pair geometry and the molecular structure of each of the following molecules or ions? (a) ClF5 (b) ClO − (c) TeCl 2− (d) PCl3 (e) SeF4 (f) PH − 84 Predict the electron pair geometry and the molecular structure of each of the following ions: (a) H3O+ (b) PCl − (c) SnCl − (d) BrCl − (e) ICl3 (f) XeF4 (g) SF2 85 Identify the electron pair geometry and the molecular structure of each of the following molecules: (a) ClNO (N is the central atom) (b) CS2 (c) Cl2CO (C is the central atom) (d) Cl2SO (S is the central atom) (e) SO2F2 (S is the central atom) (f) XeO2F2 (Xe is the central atom) (g) ClOF + (Cl is the central atom) 259 260 Chapter | Chemical Bonding and Molecular Geometry 86 Predict the electron pair geometry and the molecular structure of each of the following: (a) IOF5 (I is the central atom) (b) POCl3 (P is the central atom) (c) Cl2SeO (Se is the central atom) (d) ClSO+ (S is the central atom) (e) F2SO (S is the central atom) (f) NO − (g) SiO 4− 87 Which of the following molecules and ions contain polar bonds? Which of these molecules and ions have dipole moments? (a) ClF5 (b) ClO − (c) TeCl 2− (d) PCl3 (e) SeF4 (f) PH − (g) XeF2 88 Which of these molecules and ions contain polar bonds? Which of these molecules and ions have dipole moments? (a) H3O+ (b) PCl − (c) SnCl − (d) BrCl − (e) ICl3 (f) XeF4 (g) SF2 89 Which of the following molecules have dipole moments? (a) CS2 (b) SeS2 (c) CCl2F2 (d) PCl3 (P is the central atom) (e) ClNO (N is the central atom) This OpenStax book is available for free at http://cnx.org/content/col26488/1.3 Chapter | Chemical Bonding and Molecular Geometry 261 90 Identify the molecules with a dipole moment: (a) SF4 (b) CF4 (c) Cl2CCBr2 (d) CH3Cl (e) H2CO 91 The molecule XF3 has a dipole moment Is X boron or phosphorus? 92 The molecule XCl2 has a dipole moment Is X beryllium or sulfur? 93 Is the Cl2BBCl2 molecule polar or nonpolar? 94 There are three possible structures for PCl2F3 with phosphorus as the central atom Draw them and discuss how measurements of dipole moments could help distinguish among them 95 Describe the molecular structure around the indicated atom or atoms: (a) the sulfur atom in sulfuric acid, H2SO4 [(HO)2SO2] (b) the chlorine atom in chloric acid, HClO3 [HOClO2] (c) the oxygen atom in hydrogen peroxide, HOOH (d) the nitrogen atom in nitric acid, HNO3 [HONO2] (e) the oxygen atom in the OH group in nitric acid, HNO3 [HONO2] (f) the central oxygen atom in the ozone molecule, O3 (g) each of the carbon atoms in propyne, CH3CCH (h) the carbon atom in Freon, CCl2F2 (i) each of the carbon atoms in allene, H2CCCH2 96 Draw the Lewis structures and predict the shape of each compound or ion: (a) CO2 (b) NO − (c) SO3 (d) SO 2− 97 A molecule with the formula AB2, in which A and B represent different atoms, could have one of three different shapes Sketch and name the three different shapes that this molecule might have Give an example of a molecule or ion for each shape 98 A molecule with the formula AB3, in which A and B represent different atoms, could have one of three different shapes Sketch and name the three different shapes that this molecule might have Give an example of a molecule or ion that has each shape 99 Draw the Lewis electron dot structures for these molecules, including resonance structures where appropriate: (a) CS 2− (b) CS2 (c) CS (d) predict the molecular shapes for CS 2− and CS2 and explain how you arrived at your predictions 100 What is the molecular structure of the stable form of FNO2? (N is the central atom.) 101 A compound with a molar mass of about 42 g/mol contains 85.7% carbon and 14.3% hydrogen What is its molecular structure? 262 Chapter | Chemical Bonding and Molecular Geometry 102 Use the simulation (http://openstaxcollege.org/l/16MolecPolarity) to perform the following exercises for a two-atom molecule: (a) Adjust the electronegativity value so the bond dipole is pointing toward B Then determine what the electronegativity values must be to switch the dipole so that it points toward A (b) With a partial positive charge on A, turn on the electric field and describe what happens (c) With a small partial negative charge on A, turn on the electric field and describe what happens (d) Reset all, and then with a large partial negative charge on A, turn on the electric field and describe what happens 103 Use the simulation (http://openstaxcollege.org/l/16MolecPolarity) to perform the following exercises for a real molecule You may need to rotate the molecules in three dimensions to see certain dipoles (a) Sketch the bond dipoles and molecular dipole (if any) for O3 Explain your observations (b) Look at the bond dipoles for NH3 Use these dipoles to predict whether N or H is more electronegative (c) Predict whether there should be a molecular dipole for NH3 and, if so, in which direction it will point Check the molecular dipole box to test your hypothesis 104 Use the Molecule Shape simulator (http://openstaxcollege.org/l/16MolecShape) to build a molecule Starting with the central atom, click on the double bond to add one double bond Then add one single bond and one lone pair Rotate the molecule to observe the complete geometry Name the electron group geometry and molecular structure and predict the bond angle Then click the check boxes at the bottom and right of the simulator to check your answers 105 Use the Molecule Shape simulator (http://openstaxcollege.org/l/16MolecShape) to explore real molecules On the Real Molecules tab, select H2O Switch between the “real” and “model” modes Explain the difference observed 106 Use the Molecule Shape simulator (http://openstaxcollege.org/l/16MolecShape) to explore real molecules On the Real Molecules tab, select “model” mode and S2O What is the model bond angle? Explain whether the “real” bond angle should be larger or smaller than the ideal model angle This OpenStax book is available for free at http://cnx.org/content/col26488/1.3 ... Chemistry: Atoms First 2e SENIOR CONTRIBUTING AUTHORS PAUL FLOWERS, UNIVERSITY OF NORTH CAROLINA AT PEMBROKE KLAUS THEOPOLD, UNIVERSITY OF DELAWARE RICHARD LANGLEY, STEPHEN F... chemistry, fluorine chemistry, and chemical education Edward J Neth, University of Connecticut (Chemistry: Atoms First) Dr Edward J Neth earned his BS in Chemistry (minor in Politics) at Fairfield... work by Jeff Turner; credit c: modification of work by Gloria Cabada-Leman; credit d: modification of work by Roberto Verzo) Properties of matter fall into one of two categories If the property