Question

Draw the bond-line structure of all noncyclic alkanes with only four \(\mathrm{C}\) atoms.

Short answer

The noncyclic four-carbon alkanes are n-butane and isobutane (2-methylpropane).

Step-by-step solution

Understand the problem

The task requires drawing all possible noncyclic alkanes containing four carbon atoms. A noncyclic alkane is a linear or branched alkane without any ring structures.

Recognize the formula for alkanes

Noncyclic alkanes follow the general formula \((C_nH_{2n+2})\). For four carbon atoms, we use \(n=4\), therefore, the formula becomes \((C_4H_{10})\). This corresponds to butane.

Determine possible structures

With four carbon atoms, two possible noncyclic structures can be drawn: a straight chain, called n-butane, and a branched chain, called isobutane or 2-methylpropane.

Draw n-butane structure

Draw a straight-chain with four carbon atoms: \(C-C-C-C\)This is the bond-line structure of n-butane where each line represents a C-C bond.

Draw isobutane structure

Draw a branched structure: \(\begin{align*} & C \& | \& C-C-C \end{align*}\)This represents 2-methylpropane (isobutane), where a three-carbon chain has one carbon attached to the middle carbon.

Key concepts

Noncyclic alkanes

Noncyclic alkanes are a fascinating group of organic compounds. They are composed entirely of carbon and hydrogen atoms connected via single bonds. These alkanes are characterized by having a linear or branched structure without any rings or cyclic formations within their molecule. As such, they are sometimes referred to as "acyclic alkanes".
Understanding noncyclic alkanes is crucial because their simple structure forms the foundation for studying more complex organic compounds.Key features of noncyclic alkanes include:

• Single carbon-carbon (C-C) bonds, making them saturated hydrocarbons.
• A structure that can be completely linear (like n-butane) or branched (like isobutane).
• A general formula of \(C_nH_{2n+2}\), which provides an easy way to figure out their molecular composition.

These properties make noncyclic alkanes an essential starting point for students learning organic chemistry.

Alkane formula

The alkane formula is a significant concept when studying organic chemistry. It provides a standardized way to express the composition of any alkane. The general chemical formula for noncyclic alkanes is \(C_nH_{2n+2}\). This formula ensures that every carbon atom is saturated, meaning all its available valences are filled by hydrogen.For instance, when we set \(n = 4\), as in the exercise, we derive \(C_4H_{10}\). This formula indicates a four-carbon alkane, commonly known as butane.
Here's a simplified breakdown of the formula's application:

• "C" stands for carbon, and "H" stands for hydrogen.
• "n" is the variable representing the number of carbon atoms.
• "2n+2" ensures that all bonds are fulfilled by hydrogen atoms in a noncyclic structure.

Understand this formula, and you can easily predict the structure and composition of any simple alkane, simplifying your exploration of organic chemistry.

Structural isomers

Structural isomers are an intriguing aspect of organic chemistry. They are compounds with the same molecular formula but different structures, resulting in distinct properties and appearances.
For noncyclic alkanes with four carbon atoms, the two notable structural isomers are n-butane and isobutane (or 2-methylpropane). Although both share the formula \(C_4H_{10}\), their structures are strikingly different:

• n-Butane: A straight chain of four carbon atoms, represented as \(C-C-C-C\).
• Isobutane (2-methylpropane): A branched structure where a three-carbon chain has an additional carbon branching from the central carbon, depicted as:
  •   C
  • C-C-C

This variance in structure influences boiling points, reactivity, and other physical and chemical properties of the isomers. Recognizing and understanding isomers is fundamental for advanced studies in organic chemistry.

Organic chemistry

Organic chemistry is the study of carbon-based compounds, which extends far beyond the understanding of simple hydrocarbons like noncyclic alkanes. This branch of chemistry deals with the structure, properties, and reactions of organic materials, focusing on carbon's ability to form stable bonds with other elements, primarily hydrogen, oxygen, and nitrogen. The significance of organic chemistry includes:

• Diversity of Compounds: It has an immense scope, covering everything from fuels to pharmaceuticals.
• Understanding Life Processes: Provides insights into biological molecules crucial for life, like DNA and proteins.
• Innovation and Technology: Used to develop new materials like plastics, synthetic fibers, and advanced pharmaceuticals.

Studying organic chemistry opens the door to understanding the complex chemical foundations of many everyday substances. The systematic study beginning from simple molecules, like noncyclic alkanes, builds a foundation for exploring complex reactions and innovations in science and technology.