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CHEM 203 Exam 1 _______________________________ Name Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. ____ 1. Which of the following elements is a large percentage of both the earth's crust and of organic compounds? a. carbon b. nitrogen c. oxygen d. none of these ____ 2. Which of the following is characteristic of an oxygen atom in organic compounds? a. it normally forms four covalent bonds and has no unshared electron pairs b. it normally forms three covalent bonds and has one unshared electron pair c. it normally forms two covalent bonds and has two unshared electron pairs d. it normally forms one covalent bond and has three unshared electron pairs ____ 3. Which of the following is the expected H-C-H bond angle in formaldehyde, CH2O? a. 90o b. 109.5o c. 120o d. 180o ____ 4. Which of the following is the expected H-C-C bond angle in acetylene, C2H2? a. 90o b. 109.5o c. 120o d. 180o ____ 5. Which of the following is the expected H-C-H bond angle in ethylene, C2H4? a. 90o b. 109.5o c. 120o d. 180o 6. The chemical formula of urea is (NH2)2CO. How many valence electrons are associated with a molecule of urea? a. 4 b. 8 c. 16 d. 24 ____ ____ 7. Which of the following functional groups contains a nitrogen atom? a. amino b. carbonyl c. carboxyl d. hydroxyl ____ 8. The hydroxyl group is the functional group of which of the following types of compounds? a. acids b. alcohols c. aldehydes d. amines ____ 9. The functional group of aldehydes is often written as –CHO. Which of the following is true? a. the carbon atom forms two bonds b. the hydrogen atom forms two bonds c. the oxygen atom forms one bond d. none of the above is true ____ 10. What is the minimum number of carbon atoms present in a tertiary alcohol? a. 2 b. 3 c. 4 d. 5 ____ 11. What is the minimum number of carbon atoms present in a tertiary amine? a. 2 b. 3 c. 4 d. 5 ____ 12. Which of the following classes of organic compounds contains atoms other than carbon and hydrogen? a. alkanes b. alkenes c. amines d. arenes ____ 13. Which of the following is(are) characteristic of a saturated hydrocarbon? a. it contains as much solute as it can b. it contains the maximum possible number of hydrogen atoms for a given number of carbon atoms c. both (a) and (b) d. neither (a) nor (b) ____ 14. Which of the following is the methylene unit? a. CH4 b. –CH3 c. –CH2– d. ____ 15. Which of the following is the generic formula for straight chain alkanes? a. CnH2n-4 b. CnH2n-2 c. CnH2n d. CnH2n+2 ____ 16. Which of the following is the condensed structural formula of butane? a. CH3(CH2)4CH3 b. CH3(CH2)5CH3 c. CH3(CH2)6CH3 d. none of these ____ 17. What is the formula of the lightest hydrocarbon which exists as constitutional isomers? a. CH4 b. C2H6 c. C3H8 d. none of these ____ 18. Which of the following is(are) constitutional isomer(s) of pentane, CH3(CH2)3CH3? a. b. c. both (a) and (b) d. neither (a) nor (b) ____ 19. How many constitutional isomers are there with the formula C5H12? a. 2 b. 3 c. 4 d. 5 ____ 20. How many constitutional isomers are there with the formula C6H14? a. 3 b. 4 c. 5 d. 6 ____ 21. In a branched alkyl group the prefix sec- is used when the carbon with the available bonding position is bonded to how many other carbon atoms? a. 1 b. 2 c. 3 d. 4 ____ 22. When naming compounds in which there are several different substituents which of the following is true? a. we do not include prefixes when considering the order of naming substituents b. we do not consider the size of the substituents when determining the order of naming them c. both (a) and (b) are true d. neither (a) nor (b) is true ____ 23. What is the IUPAC name of a. b. c. d. propylbutane 2-ethylpentane 3-methylhexane 4-methylhexane ____ 24. Which of the following formulas describes the composition of cycloalkanes? a. CnH2n-4 b. CnH2n-2 c. CnH2n d. CnH2n+2 ____ 25. Which of the following molecules exists as cis-trans isomers? a. 1,2-dimethylcyclohexane b. 1,3-dimethylcyclohexane c. both (a) and (b) d. neither (a) nor (b) ____ 26. What is the name of a. b. c. d. cis-1-ethyl-4-methylcyclohexane cis-1-methyl-4-ethylcyclohexane trans-1-ethyl-4-methylcyclohexane trans-1-methyl-4-ethylcyclohexane ____ 27. Which of the following endings is used for compounds which contains a carbon-carbon double bond? a. -ane b. -ene c. -yne d. -yl ____ 28. Which of the following compounds with formula C5H10 has cis-trans isomers? a. 1-pentene b. 2-methyl-2-butene c. both (a) and (b) d. neither (a) nor (b) ____ 29. Which of the following is the generic formula of trienes? a. b. c. d. CnH2n CnH2n-2 CnH2n-4 none of these ____ 30. Which of the following reactions is regioselective? a. halogenation b. hydration c. both (a) and (b) d. neither (a) nor (b) ____ 31. What is the product of the addition of HBr to a. b. c. d. ____ 32. Which of the following is a secondary carbocation? a. b. c. both (a) and (b) d. neither (a) nor (b) ____ 33. Which combination of reactants will react to produce only 2-bromopentane? a. HBr and 1-pentene b. HBr and 2-pentene c. Br2 and 1-pentene d. Br2 and 2-pentene ____ 34. Which of the following is true of polyethylene? a. b. c. d. its physical properties depend on the method of preparation the polymer contains no carbon-carbon double bonds both (a) and (b) neither (a) nor (b) ____ 35. Which of the following compounds does not have a special name but is named as a derivative of benzene? a. b. c. d. none, they all have special names ____ 36. Which of the following catalysts is required for the synthesis of bromobenzene? a. FeCl3 b. H2SO4 c. nickel d. none, no catalyst is required ____ 37. Which of the following compounds is commonly called p-chlorotoluene? a. 1-chloro-4-methylbenzene b. 1-methyl-4-chlorobenzene c. 1-chloro-3-methylbenzene d. 1-chloro-2-methylbenzene ____ 38. Which of the following compounds is aniline? a. b. c. d. 39. In the space provided below, draw all possible structures of C4H8. After drawing your structures, provide the proper IUPAC name of each structure. (2 points per structure) Note: They have to be constitutional or stereo isomers to count. Additionally, multiple representations of the same structure as well as the presence of incorrect structures (improper carbon and/or hydrogen count) may lead to point deductions. 40. Write the major product for the following reaction. (3 points) CH3-CH2-CH2-CH=CH2 + HBr →