CHAPTER 12: SATURATED HYDROCARBONS

Transcription

1 CHAPTER 12: SATURATED HYDROCARBONS MULTIPLE CHOICE 1. Which of the following statements concerning organic compounds is correct? Organic compounds are found only in non-living systems. b. Organic compounds are always soluble in water. c. Organic compounds cannot be found in nature; they must be synthesized in a laboratory. d. Organic compounds always contain the element carbon. KEY: Chemistry organic chemistry saturated hydrocarbons NOT: Section The distinction between a saturated hydrocarbon and an unsaturated hydrocarbon relates to boiling points b. volatility c. number of carbon atoms present d. the number of multiple bonds present in the molecule KEY: Chemistry organic chemistry saturated hydrocarbons NOT: Section The four hydrogen atoms bonded to the central carbon atom in methane lie at the corners or apexes of a rectangle c. square b. tetrahedron d. parallelogram KEY: Chemistry organic chemistry saturated hydrocarbons NOT: Section Which of the following could not be the molecular formula for an alkane molecule? C 4 H 10 c. CH 4 b. C 5 H 14 d. C 24 H 50 KEY: Chemistry organic chemistry alkane formula NOT: Section The representation for the alkane propane is an example of a molecular formula c. an expanded structural formula b. a condensed structural formula d. a skeletal structural formula KEY: Chemistry organic chemistry alkane formula NOT: Section 12.5 Testbank General, Organic, Biological Chemistry, 6 th edition 1

2 6. Which of the following is a correct alkane structural formula? CH 3 CH 2 CH 3 c. CH 2 CH 2 CH 2 b. CH 3 CH 3 CH 2 d. CH 2 CH 3 CH 2 KEY: Chemistry organic chemistry alkane formula NOT: Section There are three 5-carbon alkane constitutional isomers. Their molecular formulas are, respectively, C 5 H 11, C 5 H 12, C 5 H 13 c. C 5 H 12, C 5 H 13, C 5 H 14 b. C 5 H 10, C 5 H 12, C 5 H 14 d. C 5 H 12, C 5 H 12, C 5 H 12 KEY: Chemistry organic chemistry alkane constitutional isomers NOT: Section Constitutional isomerism is possible in alkanes only if the number of carbon atoms present is four or more c. an even number b. five or more d. an odd number KEY: Chemistry organic chemistry alkane constitutional isomers NOT: Section Which of the following alkanes has the IUPAC name 2-methylbutane? c. b. d. 10. How many carbon atoms are present in the alkane whose IUPAC name is 2,2,4-trimethylpentane? five c. eight b. seven d. nine 11. How many hydrogen atoms are present in the molecule 2,5-dimethyloctane 18 c. 22 b. 20 d. 24 Testbank General, Organic, Biological Chemistry, 6 th edition 2

3 12. In which of the following pairs of alkanes are the two members of the pair constitutional isomers? hexane and 3-methylhexane b. 2,4-dimethylhexane and 2,4-dimethylheptane c. ethane and propane d. 3-methylnonane and 3,4-dimethyloctane KEY: Chemistry organic chemistry alkane constitutional isomers NOT: Section In which of the following alkanes are two secondary carbon atoms present? c. b. d. KEY: Chemistry organic chemistry alkane NOT: Section The minimum number of carbon atoms required to form a branched-chain alkane and a branched-chain alkyl group are, respectively, three and three. c. three and four. b. four and four. d. four and three. KEY: Chemistry organic chemistry alkane NOT: Section When the molecular formulas for cyclic and noncyclic alkanes with the same number of carbon atoms are compared, it is always found that the cycloalkane has two more hydrogen atoms. b. the same number of hydrogen atoms. c. two less hydrogen atoms. d. four less hydrogen atoms. KEY: Chemistry organic chemistry alkanes; cycloalkane formula NOT: Section Section Which of the following is an incorrect IUPAC name for a cycloalkane? cyclobutane c. 1,2-cyclopentane b. propylcyclopentane d. 3,3-cyclopentane KEY: Chemistry organic chemistry cycloalkane nomenclature NOT: Section Testbank General, Organic, Biological Chemistry, 6 th edition 3

4 17. For which of the following cycloalkanes is cis-trans isomerism possible? isopropylcyclopropane c. 1-methyl-1-propylcyclopropane b. propylcyclobutane d. 1-ethyl-2-methylcyclodecane KEY: Chemistry organic chemistry cycloalkane Cis/trans isomerism NOT: Section Which of the following is a general physical property of alkanes? Low solubility in water. c. More dense than water. b. Less volatile than water. d. More polar than water. KEY: Chemistry organic chemistry alkanes physical properties NOT: Section The most important chemical use for alkanes relates to their chemical reaction with hydrogen c. chlorine b. oxygen d. bromine KEY: Chemistry organic chemistry alkane chemical properties NOT: Section What is the common name for the halogenated hydrocarbon whose IUPAC name is 2-chloropropane? sec-propyl chloride c. propyl chloride b. ethyl chloride d. isopropyl chloride KEY: Chemistry organic chemistry halogenated alkane nomenclature NOT: Section Which of the following statements concerning saturated hydrocarbons is incorrect? Every carbon atom present has four bonds. b. All bonds present are single bonds. c. Every carbon atom present must be bonded to at least two hydrogen atoms. d. More than one correct response. e. No correct response. KEY: Chemistry organic chemistry saturated hydrocarbons NOT: Section Which of the following statements concerning cycloalkanes is correct? Molecular formula always fits the general formula C n H 2n+2. b. All are hydrocarbons. c. Each exists in two or more isomeric forms. d. More than one correct response. e. No correct response. Testbank General, Organic, Biological Chemistry, 6 th edition 4

5 KEY: Chemistry organic chemistry cycloalkane NOT: Section Which of the following is a correct structural formula for an alkane? b. c. KEY: Chemistry organic chemistry alkane formula NOT: Section The number of constitutional isomers possible for alkanes of a given molecular formula is the same as the number of hydrogen atoms present b. is double the number of carbon atoms present c. cannot be calculated in a simple way from the molecular formula KEY: Chemistry general chemistry alkane constitutional isomers NOT: Section Which of the following compounds is a constitutional isomer of CH 3 CH 2 CH 2 CH 2 CH 3? 2-methylpentane b. 2-methylbutane c. 2,2-dimethylbutane KEY: Chemistry organic chemistry alkane constitutional isomers NOT: Section In which of the following alkanes are 10 carbon atoms present? 2,3-dimethyloctane b. 3-ethyl-2,4-dimethylpentane c. 3,4-diethylhexane Testbank General, Organic, Biological Chemistry, 6 th edition 5

6 27. In which of the following alkanes does the number of substituents present equal the number of alkyl groups present? 2-methylpentane b. 2,2-dimethyloctane c. 3,3,4-trimethyloctane 28. In which of the following alkanes are 13 covalent bonds present? b. c. KEY: Chemistry organic chemistry alkane formula NOT: Section Which of the following alkanes has an IUPAC name that contains the word butane? b. c. 30. Which of the following alkane structures contain both secondary and tertiary carbon atoms? b. c. Testbank General, Organic, Biological Chemistry, 6 th edition 6

7 KEY: Chemistry organic chemistry alkane NOT: Section Which of the following statements concerning the boiling points of specific alkanes is correct? Hexane has a higher boiling point than heptane. b. Pentane has a higher boiling point than 2-methylpentane. c. Butane has a higher boiling point than cyclobutane. d. More than one correct response. e. No correct response. KEY: Chemistry organic chemistry alkane physical properties NOT: Section For which of the following alkanes are the products of complete combustion CO 2 and H 2 O? cyclobutane b. octane c. 2,3,3,4,4-pentamethylheptane KEY: Chemistry organic chemistry alkane chemical properties NOT: Section For which of the following halogenated cycloalkanes is cis-trans isomerism possible? 1,1-dichlorocyclobutane b. 1-bromo-1-chlorocyclobutane c. 1-bromo-2-chlorocyclobutane KEY: Chemistry organic chemistry halogenated alkane Cis/trans isomerism NOT: Section Which of the following cycloalkanes or cycloalkane derivatives contains 10 hydrogen atoms? methylcyclobutane b. 1,2-dimethylcyclobutane c. 1,2-dichlorocyclohexane KEY: Chemistry organic chemistry cycloalkane nomenclature NOT: Section Testbank General, Organic, Biological Chemistry, 6 th edition 7

8 35. Which of the following is a correct pairing of common and IUPAC names for halogenated hydrocarbons? ethyl chloride and dichloromethane b. isopropyl chloride and 1-chloropropane c. tert-butyl chloride and 2-chloro-2-methylpropane KEY: Chemistry organic chemistry halogenated alkane nomenclature NOT: Section Characterize EACH of the three given statements as being TRUE or FALSE and then (1) Alkanes have limited solubility in water and are less dense than water. (2) Propane is an alkane in which both 1 o and 2 o carbon atoms are present. (3) Some, but not all cycloalkanes, can exist is cis-trans isomeric forms. KEY: Chemistry organic chemistry alkane; cycloalkane Cis/trans isomerism; physical properties NOT: Section Section Section Characterize EACH of the three given statements as being TRUE or FALSE and then (1) A minimum of four carbon atoms is required in a cycloalkane. (2) The molecules 2,4-dimethylpentane and 2,4-dimethylhexane are constitutional isomers. (3) As a result of rotation about single bonds, all alkane molecules, except methane, can exist in an infinite number of conformations. KEY: Chemistry organic chemistry alkane; cycloalkane conformations; constitutional isomers; formula NOT: Section Section 12.6 Section 12.7 Testbank General, Organic, Biological Chemistry, 6 th edition 8

9 38. Characterize EACH of the three given statements as being TRUE or FALSE and then (1) Natural gas and petroleum constitute the largest and most important sources of both alkanes and cycloalkanes. (2) The number of hydrogen atoms present in an alkane is always twice the number of carbon atoms plus two more. (3) Unbranched alkane boiling points decrease as carbon chain-length increases. KEY: Chemistry organic chemistry alkane; cycloalkane formula; physical properties NOT: Section Section Section Characterize EACH of the three given statements as being TRUE or FALSE and then (1) Cis-trans isomers have the same molecular formula and also the same structural formul (2) Molecules of the compound 1,3-dichlorocyclohexane contain 12 hydrogen atoms. (3) The product from the reaction of one molecule of ethane with one molecule of Br 2 is 1,2-dibromoethane. KEY: Chemistry organic chemistry alkane; cycloalkane Cis/trans isomerism; chemical properties; formula NOT: Section Section Section Characterize EACH of the three given statements as being TRUE or FALSE and then (1) The names propyl bromide and 1-bromopropane denote the same compound. (2) Compounds with the molecular formula C 5 H 10 are alkanes and those with the formula C 5 H 12 are cycloalkanes. (3) Alkanes readily undergo combustion when ignited to form H 2 gas and elemental carbon. Testbank General, Organic, Biological Chemistry, 6 th edition 9

10 KEY: Chemistry organic chemistry alkane; cycloalkane; halogenated alkane chemical properties; formula; nomenclature NOT: Section Section Section Section Characterize EACH of the three given statements as being TRUE or FALSE and then (1) IUPAC names for cycloalkanes that have one substituent do not have any numbers in them. (2) Both propane and cyclopropane are gases at room temperature and pressure. (3) Halogenation of an alkane is an example of a substitution reaction. KEY: Chemistry organic chemistry alkane; cycloalkane chemical properties; nomenclature; physical properties NOT: Section Section Section Characterize EACH of the three given statements as being TRUE or FALSE and then (1) Both 3-ethyl-2-methylnonane and 3-propyl-2-methylnonane are correct IUPAC names for alkanes. (2) CFCs are halogenated hydrocarbons in which both Cl and F are present. (3) The simplest family of unsaturated hydrocarbons is the alkanes. KEY: Chemistry organic chemistry alkane; halogenated alkane; unsaturated hydrocarbons nomenclature NOT: Section Section 12.3 Section Characterize EACH of the three given statements as being TRUE or FALSE and then (1) Sixteen carbon atoms are present in the alkane 3-ethyl-4,5-dipropyloctane. (2) Two three-carbon alkyl groups and three four-carbon alkyl groups exist. (3) A condensed structural formula shows all atoms in a molecule but not all bonds in the molecule. Testbank General, Organic, Biological Chemistry, 6 th edition 10

11 KEY: Chemistry organic chemistry alkane; alkyl group formula; nomenclature NOT: Section Section 12.5 Section Characterize EACH of the three given statements as being TRUE or FALSE and then (1) All halogenated hydrocarbons have densities that are greater than that of water. (2) Substituents are present in some, but not all, branched chain alkane molecules. (3) There are two four-carbon branched-chain alkane constitutional isomers. KEY: Chemistry organic chemistry alkyl group; halogenated alkane physical properties NOT: Section Section Section Characterize EACH of the three given statements as being TRUE or FALSE and then (1) Methane, the simplest alkane, is a major component of the atmospheres of Jupiter and Saturn but only a minor component of Earth's atmosphere. (2) Some solid-state alkanes find use as skin-softeners and skin-protectors. (3) HFO's are fluorinated hydrocarbons in which a carbon-carbon double bond is present. KEY: Chemistry organic chemistry alkanes; halogenated alkane NOT: Section chemical connections Testbank General, Organic, Biological Chemistry, 6 th edition 11

12 46. For the following compound, which is denoted using skeletal structural formulas, select from the response list the number of hydrogen atoms present in the compound. 8 H atoms c. 12 H atoms b. 10 H atoms d. 16 H atoms KEY: Chemistry organic chemistry alkane formula NOT: Section For the following compound, which is denoted using skeletal structural formulas, select from the response list the number of hydrogen atoms present in the compound. 8 H atoms c. 12 H atoms b. 10 H atoms d. 16 H atoms KEY: Chemistry organic chemistry alkane formula NOT: Section For the following compound, which is denoted using skeletal structural formulas, select from the response list the number of hydrogen atoms present in the compound. 8 H atoms c. 12 H atoms b. 10 H atoms d. 16 H atoms KEY: Chemistry organic chemistry alkane formula NOT: Section For the following compound, which is denoted using skeletal structural formulas, select from the response list the number of hydrogen atoms present in the compound. 8 H atoms c. 12 H atoms b. 10 H atoms d. 16 H atoms KEY: Chemistry organic chemistry cycloalkane formula NOT: Section Testbank General, Organic, Biological Chemistry, 6 th edition 12

13 50. For the following compound, which is denoted using skeletal structural formulas, select from the response list the number of hydrogen atoms present in the compound. 8 H atoms c. 12 H atoms b. 10 H atoms d. 16 H atoms KEY: Chemistry organic chemistry cycloalkane formula NOT: Section Select from the response list a compound that has two secondary carbon atoms present. c. b. d. KEY: Chemistry organic chemistry alkane NOT: Section Select from the response list a compound that has both primary and quaternary carbon atoms present. c. b. d. KEY: Chemistry organic chemistry alkane NOT: Section Testbank General, Organic, Biological Chemistry, 6 th edition 13

14 53. Select from the response list a compound that has three kinds of carbon atoms present. c. b. d. KEY: Chemistry organic chemistry alkane NOT: Section Select from the response list a compound that has two alkyl groups present. c. b. d. KEY: Chemistry organic chemistry alkyl group NOT: Section Select from the response list a compound that has two substituents present. c. b. d. KEY: Chemistry organic chemistry alkane NOT: Section From the response list, select the correct molecular formula for 2,2-dimethylbutane. C 6 H 12 c. C 8 H 16 b. C 6 H 14 d. C 8 H 18 Testbank General, Organic, Biological Chemistry, 6 th edition 14

15 57. From the response list, select the correct molecular formula for 1,2-dimethylcyclobutane. C 6 H 12 c. C 8 H 16 b. C 6 H 14 d. C 8 H From the response list, select the correct molecular formula for cyclohexane. C 6 H 12 c. C 8 H 16 b. C 6 H 14 d. C 8 H 18 KEY: Chemistry organic chemistry cycloalkane nomenclature NOT: Section From the response list, select the correct molecular formula for 3-ethylhexane. C 6 H 12 c. C 8 H 16 b. C 6 H 14 d. C 8 H From the response list, select the correct molecular formula for 2,3,4-trimethylpentane. C 6 H 12 c. C 8 H 16 b. C 6 H 14 d. C 8 H For the pair of compounds, select a correct characterization from the response list: pentane and 2, 2-Dimethylpropane. are constitutional isomers b. have the same number of carbon atoms but are not constitutional isomers c. both exist in cis-trans forms d. one but not the other exists in cis-trans forms KEY: Chemistry organic chemistry alkane constitutional isomers NOT: Section For the pair of compounds, select a correct characterization from the response list: butane and cyclobutane. are constitutional isomers b. have the same number of carbon atoms but are not constitutional isomers c. both exist in cis-trans forms d. one but not the other exists in cis-trans forms Testbank General, Organic, Biological Chemistry, 6 th edition 15

16 KEY: Chemistry organic chemistry alkane; cycloalkane NOT: Section 12.2 Section For the pair of compounds, select a correct characterization from the response list: chlorocyclobutane and 1, 2-Dichlorocyclopropane. are constitutional isomers b. have the same number of carbon atoms but are not constitutional isomers c. both exist in cis-trans forms d. one but not the other exists in cis-trans forms KEY: Chemistry organic chemistry cycloalkane Cis/trans isomerism NOT: Section For the pair of compounds, select a correct characterization from the response list: 1,2-dichlorocyclobutane and 1-bromo-2-chlorocyclopentane. are constitutional isomers b. have the same number of carbon atoms but are not constitutional isomers c. both exist in cis-trans forms d. one but not the other exists in cis-trans forms KEY: Chemistry organic chemistry cycloalkane Cis/trans isomerism NOT: Section For the pair of compounds, select a correct characterization from the response list: cyclohexane and methylcyclopentane. are constitutional isomers b. have the same number of carbon atoms but are not constitutional isomers c. both exist in cis-trans forms d. one but not the other exists in cis-trans forms KEY: Chemistry organic chemistry alkane; cycloalkane NOT: Section Section From the response list, select the correct number of constitutional isomers that exist for a five-carbon alkane. two c. four b. three d. five DIF: Difficult KEY: Chemistry organic chemistry alkane constitutional isomers NOT: Section 12.6 Testbank General, Organic, Biological Chemistry, 6 th edition 16

17 67. From the response list, select the correct number of constitutional isomers that exist for a four-carbon cycloalkane. two c. four b. three d. five DIF: Difficult KEY: Chemistry organic chemistry cycloalkane constitutional isomers NOT: Section From the response list, select the correct number of constitutional isomers that exist for dichloroethanes two c. four b. three d. five DIF: Difficult KEY: Chemistry organic chemistry halogenated alkane constitutional isomers NOT: Section From the response list, select the correct number of constitutional isomers that exist for dichlorocyclopentanes. two c. four b. three d. five DIF: Difficult KEY: Chemistry organic chemistry cycloalkane constitutional isomers NOT: Section From the response list, select the correct number of constitutional isomers that exist for C 3 H 6 Cl 2. two c. four b. three d. five DIF: Difficult KEY: Chemistry organic chemistry halogenated alkane constitutional isomers NOT: Section Testbank General, Organic, Biological Chemistry, 6 th edition 17