Problem 17 - Chemistry: The Central Science in SI Units, Global Edition

Question

Give the name or condensed structural formula, as appropriate: a. (b) 2,2 -dimethylpentane (c) 4 -ethyl-1,1-dimethylcyclohexane (d) \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}_{2} \mathrm{CH}_{2} \mathrm{C}\left(\mathrm{CH}_{3}\right)_{3}\) (e) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}\left(\mathrm{C}_{2} \mathrm{H}_{5}\right) \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}\)

Step-by-Step Solution

Answer

a. Information not provided b. $\mathrm{CH}_{3}\mathrm{-}\mathrm{C}\left(\mathrm{CH}_{3}\right)_{2}\mathrm{-}\mathrm{CH}_{2}\mathrm{-}\mathrm{CH}_{2}\mathrm{-}\mathrm{CH}_{3}$ c. $\mathrm{CH}_{2}\left(\mathrm{CH}_{3}\right)_{2}\mathrm{-}\mathrm{CH}_{2}\mathrm{-}\mathrm{CH}_{2}\mathrm{-}\mathrm{CH}\left(\mathrm{CH}_{2}\mathrm{CH}_{3}\right)\mathrm{-}\mathrm{CH}_{2}\mathrm{-}\mathrm{CH}_{2}$ d. 2,5-dimethylheptane e. 3-ethylheptane

Step 1: Identify the Structure#

Since there is no information given for compound (a), we cannot provide a name or condensed structural formula. Please provide appropriate information for this compound. #b. 2,2-dimethylpentane#

Step 1: Draw the Structure#

First, we need to draw the structure of the compound based on its name. We have a pentane, which is an alkane with five carbon atoms. At the 2nd position, there are two methyl groups as substituents.

Step 2: Write the Condensed Structural Formula#

Now, we write the condensed structural formula by representing the different components of the structure. The formula should look like this: \[ \mathrm{CH}_{3}\mathrm{-}\mathrm{C}\left(\mathrm{CH}_{3}\right)_{2}\mathrm{-}\mathrm{CH}_{2}\mathrm{-}\mathrm{CH}_{2}\mathrm{-}\mathrm{CH}_{3} \] #c. 4-ethyl-1,1-dimethylcyclohexane#

Step 1: Draw the Structure#

First, we need to draw the structure based on its name. We have a cyclohexane, which is a six-membered ring with carbon atoms. At the 1st position, there are two methyl groups, and at the 4th position, there is an ethyl group as substituents.

Step 2: Write the Condensed Structural Formula#

Now, we write the condensed structural formula: \[ \mathrm{CH}_{2}\left(\mathrm{CH}_{3}\right)_{2}\mathrm{-}\mathrm{CH}_{2}\mathrm{-}\mathrm{CH}_{2}\mathrm{-}\mathrm{CH}\left(\mathrm{CH}_{2}\mathrm{CH}_{3}\right)\mathrm{-}\mathrm{CH}_{2}\mathrm{-}\mathrm{CH}_{2} \] #d. $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}_{2} \mathrm{CH}_{2} \mathrm{C}\left(\mathrm{CH}_{3}\right)_{3}$#

Step 1: Identify the Main Chain#

Start by identifying the main carbon chain. In this case, it is a linear chain of five carbon atoms with a branched structure.

Step 2: Determine Substituents and Positions#

Now, identify the substituents on the main chain and their positions. There are methyl groups at the 2nd and 5th positions.

Step 3: Name the Compound#

Finally, assign a systematic name to the compound using IUPAC nomenclature rules: 2,5-dimethylheptane. #e. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}\left(\mathrm{C}_{2} \mathrm{H}_{5}\right) \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}$#

Step 1: Identify the Main Chain#

Start by identifying the main carbon chain. In this case, it is a linear chain of seven carbon atoms with a branched structure.

Step 2: Determine Substituents and Positions#

Now, identify the substituents on the main chain and their positions. There is an ethyl group at the 3rd position.

Step 3: Name the Compound#

Finally, assign a systematic name to the compound using IUPAC nomenclature rules: 3-ethylheptane.

Key Concepts

alkane

Alkanes are a group of hydrocarbons that sit at the core of organic chemistry. They consist entirely of carbon ( C ) and hydrogen ( H ) atoms, bonded together through single bonds.
This makes them saturated hydrocarbons, since each carbon atom forms the maximum number of bonds possible. They can be arranged in either straight chains or branched forms.

Key characteristics of alkanes include:

• General formula: C _n_ H_{2n+2} for linear alkanes.
• Nonpolar compounds due to C-C and C-H bonds.
• Low reactivity, making them relatively stable.

These traits make alkanes essential in teaching the basics of chemistry, particularly in structure recognition and naming.

condensed structural formula

A condensed structural formula is a way of simplifying the representation of a molecule's structure. In organic chemistry, this is especially useful for alkanes and other hydrocarbons. Instead of showing all bonds explicitly, it groups the atoms together.
For example, ethane ( C_2H_6 ) could be represented as CH_3CH_3 , compactly showing each carbon's associated atoms.

Advantages of condensed structural formulas:

• Efficiently conveys information without unnecessary details.
• Makes it easier to discern molecular arrangements quickly.
• Helps in understanding the placement of substituents or branches.

Being adept at reading these notations is essential for mastering organic chemistry.

organic chemistry

Organic chemistry is the field of chemistry that studies carbon-containing compounds. It is an essential science, as carbon forms the backbone of most molecules in living organisms.
This discipline focuses not only on hydrocarbons like alkanes but also on a vast array of other compounds.

Key areas of organic chemistry include:

• Understanding molecular structures and functional groups.
• Synthesizing new compounds and predicting reactivity.
• Applying spectroscopy for structural analysis.

This area of chemistry underpins crucial industries, ranging from pharmaceuticals to energy production. It builds foundational knowledge for any aspiring chemist.