Question

Draw the following incorrectly named compounds and name them correctly. a. 2 -ethyl-3-methyl-5-isopropylhexane b. 2 -ethyl-4-tert-butylpentane c. 3 -methyl-4-isopropylpentane d. 2 -ethyl-3-butyne

Short answer

The correct names and structures for the given compounds are as follows: a. 2-ethyl-3-methyl-5-propylhexane b. 2-ethyl-4-(1,1-dimethylethyl)pentane c. 3-methyl-4-propylpentane d. 4-ethyl-1-butyne

Step-by-step solution

Identify errors in compound a name

The given molecule name is 2-ethyl-3-methyl-5-isopropylhexane. Since the isopropyl group is used when naming side chains, it should not be used in the context of the main chain. Let's fix this and draw the compound. ### Step 2: Draw and name compound a correctly ###

Draw and name compound a correctly

First, we'll draw the carbon skeleton of hexane with the given substituents. Then, rename the molecule, replacing the isopropyl group with its proper name of "propyl." This results in the correct name: 2-ethyl-3-methyl-5-propylhexane. ### Step 3: Identify errors in compound b usage ###

Identify errors in compound b name

The given molecule name is 2-ethyl-4-tert-butylpentane. However, as with compound a, using the tert-butyl group naming in main carbon chain is not an appropriate IUPAC naming convention. Let's fix this and draw the compound. ### Step 4: Draw and name compound b correctly ###

Draw and name compound b correctly

Draw the carbon skeleton of pentane with the given substituents. Then, rename the tert-butyl group with the name "1,1-dimethylethyl" to fit the IUPAC naming convention. This results in the correct name: 2-ethyl-4-(1,1-dimethylethyl)pentane. ### Step 5: Identify errors in compound c usage ###

Identify errors in compound c name

The given molecule name is 3-methyl-4-isopropylpentane. Just as in the previous cases, using the isopropyl group does not follow the IUPAC naming convention. Let's fix this by drawing and naming the compound correctly. ### Step 6: Draw and name compound c correctly ###

Draw and name compound c correctly

Draw the carbon skeleton of pentane with the given substituents. Then, rename the molecule, replacing the isopropyl group with the name "propyl," the correct choice according to IUPAC nomenclature. This results in the correct name: 3-methyl-4-propylpentane. ### Step 7: Identify errors in compound d usage ###

Identify errors in compound d name

The given molecule name is 2-ethyl-3-butyne. However, the numbering in the main chain is incorrect, as the triple bond should have the lowest number priority. Let's correct this and redraw the molecule. ### Step 8: Draw and name compound d correctly ###

Draw and name compound d correctly

Draw the carbon skeleton of butyne and add the ethyl substituent to the correct position. Renumber the molecule in a way that the triple bond has the lowest number priority. This results in the correct name: 4-ethyl-1-butyne.

Key concepts

Organic Chemistry

Organic chemistry is the study of carbon-based compounds, which are the building blocks of life. It explores the structure, properties, and reactivity of organic molecules. In this field, carbon atoms create strong bonds with other elements, forming a vast array of structures like chains, rings, and more complex frameworks. Organic chemistry is crucial in understanding how molecules interact in biological systems, materials synthesis, and pharmaceutical development.

• Carbon is versatile and forms stable bonds with elements like hydrogen, oxygen, nitrogen, and halogens.
• It can create long chains and rings through single, double, or triple bonds.
• IUPAC nomenclature is essential for naming organic compounds, ensuring precise communication among chemists.

This field not only delves into hydrocarbons and functional groups but also their transformation through chemical reactions. Understanding organic chemistry is fundamental for many applied sciences and industries.

Molecular Structure

Molecular structure refers to the arrangement of atoms within a molecule. Identifying this structure helps predict physical and chemical properties. In organic compounds, molecular structures are defined by the carbon framework and positioning of functional groups.

• The carbon backbone can vary, leading to different isomers with distinct properties.
• 3D geometry, such as bond angles and torsional strain, affects reactivity and stability.
• Proper molecular structure identification is essential in determining the correct IUPAC name, as seen in the exercise's solution.

Comprehension of molecular structure allows for prediction and manipulation of chemical behavior, crucial for synthesis and application in real-world scenarios.

Hydrocarbons

Hydrocarbons are organic compounds composed entirely of hydrogen and carbon. They form the simplistic basis of many organic chemicals. Depending on the type of bonding between carbon atoms, hydrocarbons are classified into different categories:

• Alkanes, with single bonds ( ), like hexane and pentane, noted in the exercise.
• Alkenes, with at least one double bond, giving rise to unique chemical properties.
• Alkynes, with one or more triple bonds, such as butyne in the exercise example.

The structure of hydrocarbons determines their saturation level and influences their physical characteristics like density and boiling point. In chemistry, hydrocarbons serve as the foundational structures upon which many functional groups are added, modifying their chemical behavior and uses.

Functional Groups

Functional groups are specific groupings of atoms within molecules that have distinct chemical properties. They are key in defining the reactivity and interaction of organic compounds. By altering these groups, chemists can modify a molecule's behavior and create a diverse range of substances.

• Common functional groups include hydroxyl (-OH), carbonyl (C=O), carboxyl (-COOH), and amine (-NH2) groups.
• Changing or adding functional groups transforms hydrocarbons into alcohols, ketones, acids, and other compound types.
• Correctly identifying functional groups is essential to accurately applying IUPAC rules in nomenclature, as errors in naming often arise from misunderstanding these groups.

Recognizing functional groups is vital in predicting a compound’s reactivity and its potential applications in fields like pharmaceuticals, materials science, and biotechnology.