Problem 56 - Chemistry: The Central Science in SI Units, Global Edition

Question

Write the condensed structural formula for each of the following compounds: (a) 2-ethyl-1-hexanol, (b) methyl phenyl ketone, \((\mathbf{c})\) para- bromobenzoic acid, (d) butyl ethyl ether, \((\mathbf{e}) N, N\) -dimethylbenzamide.

Step-by-Step Solution

Answer

The condensed structural formulas for the given compounds are as follows: (a) \(CH_3CH(OH)CH(CH_3)CH_2CH_2CH_3\), (b) \(C_6H_5COCH_3\), (c) \(C_6H_4BrCOOH\), (d) \(C_4H_9OCH_2CH_3\), (e) \(C_6H_5CON(CH_3)_2\).

Step 1: Break down the name into its parts

The name 2-ethyl-1-hexanol tells us that there is a 6-carbon chain (hexane), with an alcohol group in the first carbon and an ethyl group in the second carbon. This should give a molecule with the following condensed structural formula: \(CH_3CH(OH)CH(CH_3)CH_2CH_2CH_3\). 2. methyl phenyl ketone

Step 2: Break down the name into its parts

The name methyl phenyl ketone tells us that there is a ketone group formed between a methyl (CH3) and a phenyl (C6H5) group. This should give a molecule with the following condensed structural formula: \(C_6H_5COCH_3\). 3. para-bromobenzoic acid

Step 3: Break down the name into its parts

The name para-bromobenzoic acid tells us that there is a benzoic acid (C6H5COOH) group with a bromine atom in the para position (opposite to the carboxyl group). This should give a molecule with the following condensed structural formula: \(C_6H_4BrCOOH\). 4. butyl ethyl ether

Step 4: Break down the name into its parts

The name butyl ethyl ether tells us that there is an ether linkage between a butyl group (C4H9) and an ethyl group (C2H5). This should give a molecule with the following condensed structural formula: \(C_4H_9OCH_2CH_3\). 5. N, N-dimethylbenzamide

Step 5: Break down the name into its parts

The name N, N-dimethylbenzamide tells us that there is a benzene ring with an amide group (CONH2) substituted in it, and the nitrogen atom of the amide group is attached to two methyl groups. This should give a molecule with the following condensed structural formula: \(C_6H_5CON(CH_3)_2\).

Key Concepts

Organic Chemistry

Organic chemistry is the science that studies compounds mainly composed of carbon and hydrogen, often containing other elements like oxygen, nitrogen, sulfur, and halogens. This branch of chemistry is essential as it forms the foundation for various fields, from biology to medicine.
It explains how carbon atoms bond with other atoms to create thousands of diverse structures and compounds.
Some key ideas in organic chemistry include understanding how atoms bond, how these bonds form three-dimensional structures, and how molecular changes impact chemical reactions.

• Carbon's ability to form four covalent bonds makes it uniquely suited to create complex molecules.
• Organic compounds can range from simple molecules like methane (CH_4) to complex ones like proteins and DNA.
• Functional groups like alcohols, ketones, and ethers define how these compounds behave chemically.

By studying organic chemistry, you gain insights into molecular behavior, a crucial part of understanding life and industrial processes.

Molecular Structures

In organic chemistry, understanding molecular structures is crucial for predicting how a compound will react and what properties it will exhibit. Molecular structures describe the arrangement of atoms within a molecule and the connections between them.
These structures are often depicted in the form of Lewis structures, skeletal formulas, or condensed structural formulas.

• Condensed structural formulas provide a simplified view of molecules, focusing on groups of atoms bonded together and the functional groups present.
• For example, in the molecule 2-ethyl-1-hexanol, the condensed structural formula is: \(CH_3CH(OH)CH(CH_3)CH_2CH_2CH_3\).
  
• This tells us that the main chain has six carbon atoms with an alcohol group on the first carbon and an ethyl group on the second carbon.
• Recognizing these patterns helps deduce the actual shape and angles between atoms, key for understanding how molecules interact in various environments.

A solid grasp of molecular structures allows chemists to visualize molecules, crucial for synthesis and analysis.

Functional Groups

Functional groups are specific clusters of atoms within molecules that serve as the primary determinant of chemical properties. Each functional group exhibits consistent and predictable chemistry across various molecules.

• Common functional groups include alcohols (\(OH\)), ketones (\(CO\)), and ethers (\(C-O-C\)).
• For methyl phenyl ketone, the ketone group is crucial, represented in the formula: \(C_6H_5COCH_3\).
• Understanding the functional groups present in a compound helps predict its reactivity and interaction with other compounds.
• These groups dictate attributes like polarity, solubility, and boiling points.

Learning about functional groups equips students with the tools to anticipate how a change in the molecular structure will influence a compound's behavior in reactions and its interactions in biological and synthetic environments.