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Chem 121 Fritsch Ch 10 - 11 Practice Problems The following problems are intended to provide you with additional practice in preparing for the exam. Questions come from the textbook, previous quizzes, previous exams, and other sources. A solutions manual is supplied in a separate document. 1. Sodium nitrite is an ionic compound containing a polyatomic ion. Answer the following questions relative to nitrite. a. Give the Lewis structure of nitrite. b. Give the hybridization of nitrogen. c. Illustrate the orbital overlaps in nitrite including the number of electrons in each bond. If σ or π bonds are present clearly show their presence in the structure. 2. For the molecule, CNClH2, select the answer with the correct number of and bonds in the Lewis structure. 3. Which of the following cannot be a correct Lewis structure given its molecular formula? HCN NO SO3 4. The molecule below is atorvastatin, the active ingredient in Lipitor. COCl2 Chem 121 Fritsch Fill in the answer for the following aspects of atorvastatin’s structure. The approximate bond angle at a. The hybridization at b. The number of hydrogen atoms bonded at c. The hybridization at d. The hybridization at e. The number of hydrogen atoms bonded at e. The hybridization at f. 5. For the following pairs of elements in a covalent bond, which picture is correct? 6. You are given an amino acid that is either glycine (HC2H4NO2) or alanine (HC3H6NO2), both of which are monoprotic acids. To determine which compound you have, you dissolve 0.697 g of the white solid into 25.00 mL of deionized water and titrate that solution with 17.32 mL of 0.5365 M sodium hydroxide. Identify the acid. 7. Draw 3 acceptable Lewis structures that are isomers of C2NH2Cl. 8. Which of the following orbital overlaps diagrams will give a pi bond? A B C D E Chem 121 Fritsch 9. For the following compounds, provide the names for the electronic and molecular geometries and draw the molecular geometry. Is there an overall molecular dipole moment? Compound Electronic geometry name NH3 BrF5 I3- SO32- NO2 Molecular geometry name Molecular geometry drawing Molecular dipole moment? (Y/N) Chem 121 Fritsch 10. What are the electronic and molecular geometries of POF3? 11. Draw the isomers of PH2Cl3. 12. Of NH3, CaCl2, PCl5, K2O which have predominantly ionic bonding? 13. Based on the Lewis structure for thiocyanate (SCN-, shown), what are the formal charges on the atoms? 14. The structure of allene, C3H4, contains two CH2 members. Each CH2 fragment is in one plane but the two planes are perpendicular to one another. Draw the Lewis structure of allene. Inside the box below describe why all of its atoms cannot be in the same plane. 15. Place the following in order of increasing bond length: O2, N2, Br2, BrCl Chem 121 Fritsch 16. Draw the Lewis structures, VSEPR shape including molecular geometry name, and hybridization of the following: Formula Lewis structure VSEPR and molecular geometry Hybridization at central atom ClF2- ClF3 ClO2- ClF5 17. Draw the line drawing of H2NCH2CHCHCHO. Label the hybridization at each central atom. Chem 121 Fritsch 18. For the the following compounds, answer the following questions: CO32-, SiCl4, ICl3, PH3, PF6-, SO2, H2SO4 a. Which of the following utilize expanded valence for their Lewis structures? b. Which of the following have a non-zero formal charge on one (or more) of the atoms? Which atom? c. What is the hybridization for each central atom? d. Which of the molecules are polar? Draw in the molecular dipole moment into a VSEPR drawing. e. Which of the molecules have resonance structures? 19. For hydrogen azide, HN3, the bond lengths between two of the nitrogens is 113 pm which it is 124 pm for the other pair of nitrogen atoms. Also, the H-N-N bond angle is 112 °. Draw a Lewis structure consistent with this data. 20. The bond dissociation energy of ozone (O3) is 364 kJ/mol. The bond dissociation energy for O-O is 142 kJ/mol, and for O=O it is 498 kJ/mol. Using Lewis structures, explain these data. 21. Give the bond angles in the following compounds. a. CCl4 b. PF5 c. SiF62- d. H2S e C2H2