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8: Homework Solutions

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    Hydrocarbons

    (01) Answers may vary.

    ch8q1answer.png

    (02)

    1. F
    2. F
    3. T
    4. F

    (03) Saturation: when an organic compound contains the maximum number of C to H bonds and they are all single bonds

    1. saturated
    2. unsaturated
    3. unsaturated
    4. saturated
    5. saturated

    (04)

    1. Hydrophobic
    2. H-bond incapable
    3. Lipid-soluble
    4. Covalent bonding
    5. Many combinations

    (05) The other compound most likely contains a structural feature that can H-bond with an O-H or N-H structural feature.

    Saturated Hydrocarbons

    (06)

    1. F
    2. T
    3. F
    4. F
    5. F

    (07)

    ch8q7answer.png

    (08) alkyne: linear; alkene: trigonal planar; alkane: tetrahedral and considered ‘saturated’

    (09)

    1. conformers
    2. completely different
    3. completely different
    4. identical
    5. identical

    Writing Structures

    (10)

    1. CH3CH(CH3)C(CH3)2CH3 or CH3CH(CH3)C(CH3)3
    2. CH3CH(CH3)CH(CH2CH3)CH(CH3)CH3
    3. CH3CH(CH3)C(CH3)2CH(CH3)2
    4. CH3C(CH3)2C(CH3)2C(CH3)2C(CH3)2CH3
    5. CH3CH(CH3)CH(CH3)2

    (11)

    1. CH3CH2C(CH3)2CH2CH3; 3,3-dimethylpentane
    2. CH2=CHCH(CH3)CH2CH3; 3-methyl-1-pentene
    3. CH3C​=CC(CH3)3; 4,4-dimethyl-2-pentyne
    4. CH3CH(CH3)2C(CH3)2CH3 or CH3CH(CH3)2C(CH3)3;2,2,3,3-tetramethylbutane
    5. C6H5CH2CH3; ethylbenzene

    (12)

    1. 3,4-diethyl-3-methylhexane
    2. 2,3,3,4-tetramethylhexane
    3. 2,3,4-trimethyl-2-pentene
    4. 3,3-dimethyl-1-butyne
    5. 3-ethyl-2,4-dimethylpentane

    (13)

    ch8q13answer corrected.png

    (14)

    ch8q14answer.png

    (15) unsaturated (CnH2n) vs saturated (CnH2n+2)

    ch8q15answercomplete.png

    Unsaturated Hydrocarbons: Alkenes and Alkynes

    (16)

    1. aromatic
    2. alkene
    3. alkene
    4. diene
    5. polyene

    Naming Hydrocarbons

    (17)

    1. heptane
    2. trans-2-pentene
    3. ethyne or acetylene (The common name is used more frequently than the IUPAC name.)
    4. nonane
    5. 1-butene

    (18)

    1. 3-ethyl-2,2,3-trimethylhexane; C11H24
    2. 2,3,5-trimethylhexane; C10H22
    3. 3-ethyl-2,2,5-trimethylheptane; C12H26
    4. 1-ethyl-2-methylcyclohexane; C9H18
    5. 3,3-diethylpentane; C9H20

    (19)

    ch8q19answer.png

    (20)

    1. 2,2-dimethylbutane
    2. 3,4,5-trimethylheptane
    3. 1-butyl-2-methylcyclopentane
    4. 2,3,3,4,4,5,6-heptamethylheptane
    5. 1,2,3,5-tetramethylcyclohexane

    (21)

    ch8q21answer.png

    (22)

    1. 3-methylcyclobutene
    2. 3,4-dimethyl-2-pentene
    3. 5,6-dimethyl-1-heptene
    4. trans-2-octene
    5. 4-methyl-2-pentyne

    (23)

    ch8q23answer.png

    (24)

    ch8q24answer.png

    (25)

    1. 2,5-dimethyl-3-hexyne
    2. 4,4-dimethyl-2-pentyne
    3. 1-pentyne
    4. 3-ethyl-3,4-dimethyl-1-pentyne
    5. 2,2,5-trimethyl-3-hexyne

    Aromatic Hydrocarbons

    (26)

    ch8q26answer.png

    (27)

    ch8q27answer.png

    (28)

    ch8q28answer.png

    (29)

    1. Vitamin B2
    2. Vitamin B5 has 4 continuous C's and Vitamin B2has 5 continuous in the aromatic ring.
    3. Vitamin B5 C9H17NO5 and Vitamin B2 C17H20N4O6
    4. Water soluble because there are less than 4 non-polar carbons per polar group.
    5. Ye4s

    (30) A

    Additional Exercises

    31. organic

    32. Methylcyclopentane and cyclohexane both have the chemical formula of C6H12, so they are structural isomers.

    33.

    1. Two numbers are needed to indicate two substituents; 2,2-dimethylpropane.
    2. The lowest possible numbers were not used; 2,2,3-trimethylbutane.
    3. An ethyl substituent is not possible on the second carbon atom; 3,5-dimethylheptane.
    4. A propyl substituent is not possible on the fifth carbon atom; 3,4,5-trimethyloctane.

    ch8q33answer.png

    34.

    1. C3H8 + 5O2 → 3CO2 + 4H2O
    2. 2C8H18 + 25O2 → 16CO2 + 18H2O
    35. 7.6 lb

    36.

    ch8q36answer.png

    37.

    1. same
    2. structural isomers
    3. structural isomers

    38.

    1. i & ii (C7H14) and iii & iv (C7H16)
    2. i & v

    8: Homework Solutions is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts.

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