Chemistry: Organic Chemistry: Nomenclature and Isomers Worksheet

Question 1

Name the compound with the condensed structural formula CH3-CH2-CH3.

Accepted Answer

The compound is propane because it has a three-carbon continuous chain and only single bonds.

Question 2

Name the compound with the condensed structural formula CH3-CH(CH3)-CH2-CH3.

Accepted Answer

The compound is 2-methylbutane because the longest chain has four carbons and a methyl group is attached to carbon 2.

Question 3

Name the alcohol with the condensed structural formula CH3-CH2-CH2-CH2-OH.

Accepted Answer

The compound is butan-1-ol because it has a four-carbon chain and the hydroxyl group is attached to carbon 1.

Question 4

Name the alkene with the condensed structural formula CH3-CH2-CH=CH2.

Accepted Answer

The compound is but-1-ene because the four-carbon chain contains a double bond starting at carbon 1 when numbered from the nearest end.

Question 5

Name the compound with the condensed structural formula CH3-CH(CH3)-CH(CH3)-CH3.

Accepted Answer

The compound is 2,3-dimethylbutane because the longest chain has four carbons and methyl groups are attached to carbons 2 and 3.

Question 6

Write a condensed structural formula for 3-ethyl-2-methylhexane.

Accepted Answer

A correct condensed structural formula is CH3-CH(CH3)-CH(CH2CH3)-CH2-CH2-CH3. This shows a six-carbon parent chain with a methyl group on carbon 2 and an ethyl group on carbon 3.

Question 7

List all three structural isomers of C5H12 by IUPAC name.

Accepted Answer

The three structural isomers of C5H12 are pentane, 2-methylbutane, and 2,2-dimethylpropane. They have the same molecular formula but different carbon skeletons.

Question 8

Explain what structural isomers are, using C4H10 as an example.

Accepted Answer

Structural isomers are compounds with the same molecular formula but different connections between atoms. For C4H10, butane has a straight four-carbon chain, while 2-methylpropane has a branched chain.

Question 9

Describe the difference between cis-2-butene and trans-2-butene.

Accepted Answer

In cis-2-butene, the two CH3 groups are on the same side of the double bond. In trans-2-butene, the two CH3 groups are on opposite sides of the double bond.

Question 10

Name the compound CH3-CO-CH3 and identify its functional group.

Accepted Answer

The compound is propanone. Its functional group is a ketone because the carbonyl carbon is bonded to two carbon groups.

Question 11

Name the compound CH3-CH2-COOH and identify its functional group.

Accepted Answer

The compound is propanoic acid. Its functional group is a carboxylic acid because it contains the -COOH group.

Question 12

Name CH3-CH2-CH2-Br and give the name of one structural isomer with the same molecular formula.

Accepted Answer

The compound is 1-bromopropane. One structural isomer with the same molecular formula is 2-bromopropane, where the bromine atom is attached to the middle carbon.

Question 13

Name a benzene ring with one methyl group attached.

Accepted Answer

The IUPAC name is methylbenzene. The common name toluene is also widely used for this compound.

Question 14

Are 2-methylpentane and 3-methylpentane structural isomers? Explain your answer.

Accepted Answer

Yes, 2-methylpentane and 3-methylpentane are structural isomers because they both have the formula C6H14, but the methyl branch is attached at a different position on the carbon chain.

Question 15

Explain the difference between a saturated hydrocarbon and an unsaturated hydrocarbon. Use hexane and hex-1-ene as examples.

Accepted Answer

A saturated hydrocarbon has only single carbon-carbon bonds, so hexane is saturated. An unsaturated hydrocarbon has at least one double or triple carbon-carbon bond, so hex-1-ene is unsaturated because it contains a carbon-carbon double bond.

Chemistry: Organic Chemistry: Nomenclature and Isomers

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