43 8.4 Naming and Drawing Hydrocarbons

Practice questions

1. Which name is correct for this structure? The structure description: five carbons with twelve hydrogens in a straight chain drawn in a line structure format.
   1. 1. Hexane
      2. Pentane
      3. Propane
      4. Pentene
2. What name is best for this molecule? The structure description: five carbons with hydrogens in a straight chain drawn in a line structure format. The second and fourth carbons each have methyl groups.
   1. 1. 2,4-Dimethylpentane
      2. 1,1-3,3-Tetramethylpropane
      3. Heptane
      4. 2,4-Dimethylheptane
3. What name is best for this molecule? The structure description: six carbons with hydrogens in a straight chain drawn in a line structure format. The second and fourth carbons each have methyl groups.
   1. 1. 3,5,5-Trimethylpentane
      2. Dimethyloctane
      3. 2,4-Dimethylhexane
      4. 3,5-Dimethylhexane
4. Which name is best for this structure? The structure description: five carbons with a carbon-carbon triple bond between the first and the second carbons drawn in a line structure format.
   1. 1. 1-Pentene
      2. Pent-1-yne
      3. 1-Butyne
      4. Pent-4-yne
5. What name is best for this structure? The structure description: four carbons with a carbon-carbon triple bond between the second and the third carbons drawn in a line structure format.
   1. 1. Eth-2-yne
      2. But-2-yne
      3. Z-butyne
6. Choose the correct IUPAC names from the given list for the following structures: 2-ethyl-1-hexene, cyclohexane, cyclopentane, 5-methyl-1-hexene, 2.3-dimethyl-1-butene, 2-methyl-2-pentene, 3-ethyl-2-pentene.
   1. 1. A structure with seven carbons in a straight chain and [latex]\ce{CH_{2}}[/latex] group attached to the third carbon by a carbon-carbon double bond.
      2. A five-carbon ring with a one-carbon double bond.
      3. A structure with five carbons in a straight chain, a [latex]\ce{CH_{3}}[/latex] group attached to the second carbon and a carbon double bond between the second and the third carbons.
      4. A structure with four carbons in a straight chain, a [latex]\ce{CH_{3}}[/latex] group attached to the second and third carbon each and a carbon double bond between the third and the fourth carbons.
      5. Six carbon ring with one carbon double bond
      6. A structure with six carbons in a straight chain, a [latex]\ce{CH_{3}}[/latex] group attached to the fifth carbon and a carbon double bond between the first and the second carbons.
      7. A structure with five carbons in a straight chain, a [latex]\ce{C_{2}H_{5}}[/latex] group attached to the third carbon and a carbon double bond between the second and the third carbons.
7. Which of the following is the correct structure of 2-Methyl-1-pentene?
   1. 1. A structure with five carbons in a straight chain, a [latex]\ce{CH_{3}}[/latex] group attached to the second carbon and a carbon double bond between the first and the second carbons.
      2. A structure with five carbons in a straight chain, a [latex]\ce{CH_{3}}[/latex] group attached to the fourth carbon and a carbon double bond between the second and the third carbons.
      3. A structure with five carbons in a straight chain, a [latex]\ce{CH_{3}}[/latex] group attached to the fourth carbon and a carbon triple bond between the second and the third carbons.
8. What is the IUPAC name of this structure? The structure description: a structure with seven carbons in a straight chain, a [latex]\ce{C_{2}H_{5}}[/latex] group attached to the fifth carbon and a carbon triple bond between the third and the fourth carbons.
   1. 1. 5-methyl-2-heptyne
      2. 5-ethyl-2-heptene
      3. 5-ethyl-2-heptyne
      4. 3-ethyl-5-heptyne
9. What is the IUPAC name of this structure? The structure description: a structure with four carbons in a straight chain, a [latex]\ce{CH_{3}[/latex] group attached to the second carbon and a carbon double bond between the first and the second carbons.
   1. 1. 2-propyl-1-propyene
      2. 2-Methyl-1-butane
      3. 3-Methyl-3-butene
      4. 2-Methyl-1-butene
10. What is the IUPAC name of this molecule? The structure description: a structure with three carbons in a straight chain and a carbon double bond between the first and the second carbons.
    1. 1. 1-Propene
       2. 2-Propene
       3. 1-Propane
       4. 2-Propyne

Answers

1. b
2. c
3. a
4. b
5. b
6. 1. 1. 2-ethyl-1-hexene,
      2. cyclopentane,
      3. 2-methyl-2-pentene,
      4. 2.3-dimethyl-1-butene,
      5. cyclohexane,
      6. 5-methyl-1-hexene,
      7. 3-ethyl-2-pentene.
7. a
8. c
9. d
10. a