CHEMISTRY 104 – Practice Problems #1 Chs. 8, 9, 11 - Chem 103; Ch. 24 - organic, proteins, fats, carbohydrates; Ch 12. - polymers Prepared by Dr. Tony Jacob http://www.chem.wisc.edu/areas/clc (Resource page) Suggestions on preparing for a chemistry exam: 1. Organize your materials (quizzes, notes, etc.). 2. Find out exactly what material/chapters are and are not on the exam 3. Usually, a good method to prepare for a chem exam is by doing lots of problems. Re-reading sections of a chapter is fine, but re-reading entire chapters takes up large amounts of time that generally is better spent doing problems. 4. Old exams and quizzes posted by your instructor should be completely worked though. Below are additional practice problems. You might want to do the questions in a different order than written. Good Luck! 5. Lecture sections in Chem 104 can cover different material especially in the organic/biochem section. Do only problems that involve the topics covered in your lecture section. CHAPTERS 8, 9, and 11 – REVIEW 1. a. What’s the hybridization of the N atom marked “A”? b. What’s the angle formed by the N–C–C atoms marked “B”? c. What’s the bond order for the bond labeled “C”? d. What’s the electron domain geometry around the C atom labeled “D”? e. What orbitals overlap to generate the bonds labeled “E” f. What’s the electron domain geometry around the C atom labeled “F”? 2. Given the following molecule, answer the questions. a. What is the molecular geometry around the C atom labeled “A”? b. What is the hybridization of the C atom labeled “B”? c. How many π bonds are in this molecule? d. What is the hybridization of the O atom labeled “C”? e. What is the angle centered around the C labeled “D”? f. What is the molecular geometry around the O atom labeled “C”? g. What is the hybridization of the N atom? h. What is the electron domain geometry around the N atom? i. What orbitals overlap to form the bond labeled “E” between the C and C atoms? j. What orbitals overlap to form the bond labeled “F” between the O and C atoms? 3. Draw the resonance structure for this molecule. 4. Which molecule has the shortest C–O bond length? a. OH b. O c. O d. OO- e. All C–O bonds are the same length CHAPTER 24 – ORGANIC – Functional groups and naming mainly 5. Circle all functional groups and where appropriate, label functional groups cis/trans, or 1˚, 2˚, or 3˚. OHNOOHOHO (take a nap)OO-OHNOABOHCDEFONOHOABCFED6. Which functional group is nonpolar? a. alcohol b. alkene c. carboxylic acid d. amine e. all are polar 7. Draw the following molecules in a 1) bond line structure, 2) showing all bonds, atoms, and lone pairs of electrons, and 3) as a dash-wedge structure showing all bonds and all atoms. a. acetone b. toluene 8. Which molecule could contain a triple bond? a. C2H6 b. C6H6 c. C4H8 d. C3H8 e. None of these 9. Which of the following statements is false? a. Methanol will have a higher boiling point than methane. b. Dimethylamine ((CH3)2NH) will react with hydrochloric acid. c. Butanoic acid will have a higher melting point than diethylether (CH3CH2–O–CH2CH3). d. Propanol is insoluble in water. e. An enantiomer pair of isomers will have the same melting points. 10. Which molecule would be expected to be most soluble in water? a. b. OH c. OHHO OH d. O e. 11. (The next question is on gasoline; if not covered skip.) I. Which compounds are found in gasoline? a. b. c. d. e. II. Which octane rating has the highest percentage of heptane? a. 25 b. 55 c. 83 d. 88 e. 92 III. Which statement about gasoline is incorrect? If all are correct select answer “e”. a. The distillation process separates the crude oil into fractions based on boiling points. b. Catalytic cracking breaks long carbon chain molecules into smaller ones. c. Reforming changes straight-chain molecules into branched molecules. d. Oxygenated gasoline is gasoline that contains added oxygenated-chemicals so the gasoline burns more completely and reduces emissions. e. All of the above are correct. 12. Given the chemical formula C4H8O, draw a molecule that contains the functional groups listed below. a. A molecule that contains a cyclic ether. b. A molecule that contains a cyclic alcohol. c. A molecule that contains both an alcohol and alkene. d. A molecule that contains both an ether and an alkene. (Note: There are many different possible answers to each of the above questions.) (watch some TV)13. Give the systematic name for each molecule (do not use common names). (Skip molecules with functional groups not covered in your lecture.) a. Cl b. c. d. e. 14. Which functional group does not exhibit H-bonding? a. 1˚ alcohol b. 2˚ amine c. carboxylic acid d. ether e. all exhibit H-bonding 15. Which functional group does not contain a carbonyl? a. aldehyde b. ether c. ketone d. carboxylic acid e. all contain a carbonyl CHAPTER 24 – ORGANIC – Isomers mainly 16. Which pair of molecules is correctly assigned to the isomer name? a. Enantiomer pair: CH3CCl OHHCH3CHClOH b. Structural isomers: c. Geometric isomers: d. Structural isomers: 17. cis-2-butene and trans-2-butene exist as different isomers because it is not possible to rotate through the double bond. Why is it so difficult to rotate through the double bond? 18. a. Draw all four structural and geometric isomers of C3H5Cl. Do not include cyclic compounds. b. Draw all seven structural and geometric isomers of C3H4Cl2. Do not include cyclic compounds. c. Using C6H12, draw all eight 5-carbon chain structural and geometric isomers. Do not include cyclic compounds or molecules with a carbon chain length other than 5 carbons long. d. Draw all four ester isomers of C4H8O2. e. Draw all seven alkyne isomers of C6H10. (eat a Snickers bar)19. Which molecule is chiral? Select answer “e” if none are chiral. a. NHHCHHCOOH b. OO Cl c. Br d. e. none are chiral 20. How many chiral carbons does the molecule below have? CCCCCCCO HH HH OHHO HHO HH HH O 21. Match the information below with a chemical listed below. If no molecule matches, write “none.” a. ester b. has geometric isomers c. optically active d. has C–C bond order of 1.5 e. is a secondary alcohol f. will react with acetic acid to form an amide g. creates a solution in water with pH < 7 h. has sp hybridized carbon atoms I. OHOHOH II.