Question

What are structural isomers? Which is the smallest alkane that has a structural isomer? Draw structures to illustrate the isomers.

Short answer

Structural isomers are molecules with the same molecular formula but different structures, resulting in different physical and chemical properties. The smallest alkane with a structural isomer is butane (\(C_4H_{10}\)). There are two structural isomers of butane: 1. Straight chain butane: H H H H | | | | H-C-C-C-C-H | | | | H H H H 2. Branched chain isomer (iso-butane): H H H | | | H H H-C-C-C-H | | | | H-C H H | H These two isomers share the same molecular formula, \(C_4H_{10}\), but have different structures and properties.

Step-by-step solution

Recall the general formula for alkanes

Alkanes are hydrocarbons with single bonds between the carbon atoms. The general formula for alkanes is \(C_nH_{2n+2}\), where n represents the number of carbon atoms in the molecule.

Investigate alkanes with increasing carbon atoms

Starting with the simplest alkane, methane (\(CH_4\)), we can examine the structural possibilities as we increase the number of carbon atoms. Methane has only one carbon atom, so there is only one possible structure. Next, we move to ethane (\(C_2H_6\)). This molecule has two carbon atoms, which are both bonded to each other. There is still only one possible structure. When we reach propane (\(C_3H_8\)), there are three carbon atoms. However, there is only one way to arrange these carbon atoms in a straight chain, and no branching is possible. Hence, propane has no structural isomers.

Examine butane and find its structural isomers

When we reach butane (\(C_4H_{10}\)), there are four carbon atoms. Now, it is possible to have a different arrangement of carbon atoms, resulting in a structural isomer. There are two possible structures for butane: 1. A straight chain of four carbon atoms. 2. A branched chain with three carbon atoms in the main chain and one carbon atom attached as a branch to the second carbon atom. These two structures represent the two structural isomers of butane. They share the same molecular formula, \(C_4H_{10}\), but have different structures and properties.

Draw the structures of butane and its structural isomer

To illustrate the isomers of butane, we can draw the following structures: 1. Straight chain butane: H H H H | | | | H-C-C-C-C-H | | | | H H H H 2. Branched chain isomer (iso-butane): H H H | | | H H H-C-C-C-H | | | | H-C H H | H In conclusion, the smallest alkane that has a structural isomer is butane, and it has two structural isomers: the straight chain (n-butane) and the branched chain (iso-butane).

Key concepts

Alkanes 101

Alkanes are a fascinating group of hydrocarbons, consisting solely of carbon and hydrogen atoms. They are the simplest type of organic compounds due to their single bond structures. The primary feature that sets alkanes apart is their general formula, which is \( C_nH_{2n+2} \). Here, \( n \) represents the number of carbon atoms within the molecule. As you add more carbon atoms, alkanes become longer and form different structures.

• They only contain single bonds between carbon atoms.
• This single-bonded structure makes them saturated hydrocarbons.

Understanding alkanes helps us grasp more complex organic chemistry concepts like isomerism and reactivity.

Understanding Molecular Structures

Molecular structures are the backbone of chemistry, helping to visualize how atoms in a molecule connect to one another. By understanding molecular structures, one can predict the properties and behavior of a compound. This is crucial for understanding complex chemical phenomena like isomerism. Molecular structures can vary:

• Linear arrangements, such as straight-chain alkanes.
• Branched configurations, which lead to structural isomers.

By drawing molecular structures, chemists can analyze and predict how molecules will react under different conditions. This is why visualization is a fundamental part of learning chemistry.

Dive Into Butane Isomers

When exploring butane, with the molecular formula \( C_4H_{10} \), students encounter the exciting concept of structural isomers for the first time. Butane can exhibit more than one structural form due to its four carbon atoms. While all alkanes share the same molecular formula, they can differ in their arrangement, leading to different isomers.In the case of butane: - There is the straight-chain form known as **n-butane**. This structure consists of a single continuous chain of four carbon atoms.- The other isomer is **iso-butane** (or isobutane), where the main chain consists of three carbons, with the fourth branching from the second carbon in the chain.Each isomer shares the same chemical formula but has unique physical and chemical properties. This illustrates how a simple alteration in structure can lead to variations in a compound's behavior.

Exploring Organic Chemistry

Organic chemistry revolves around the study of carbon-containing compounds, primarily including those formed with hydrogen. It is a vast and essential branch of chemistry with a profound impact on various industries and biological processes. Alkanes, as the simplest organic compounds, serve as a starting point for delving deeper into organic chemistry concepts.

• Organic compounds are classified based on their functional groups and structural features.
• The study involves understanding reactivity patterns and synthesis of complex molecules.

The versatility of carbon atoms in forming diverse structures is at the heart of why organic chemistry is so richly varied. By exploring organic chemistry, students can appreciate how structural diversity leads to the vast array of organic compounds essential in everyday life.