Alkanes - Formula, List, Structure, Definition, Examples, Videos

Alkanes Explained: Formulas, Structures, & More

Welcome to our fascinating journey into the world of alkanes! If you’ve ever wondered about the building blocks of organic compounds, then alkanes are where it all starts. From their formulas to their structures and properties, we’re here to unravel the mysteries of these unique hydrocarbons. Whether you’re a chemistry enthusiast or simply curious about the world around you, this article will provide you with a solid foundation in understanding alkanes.

Key Takeaways

  • Alkanes are organic compounds consisting of single-bonded carbon and hydrogen atoms.
  • They can be categorized into chain alkanes, cycloalkanes, and branched alkanes.
  • Alkanes have the general formula CnH2n+2 and examples include methane, ethane, propane, butane, pentane, and hexane.
  • Alkanes are nonpolar and insoluble in water but soluble in organic solvents.
  • The physical properties of alkanes, such as boiling point and melting point, vary with molecular weight.

Alkanes Formula and Condensed Structures

The structural formulas of alkanes can be written in condensed form, which represents the arrangement of carbon and hydrogen atoms in the molecule. The formula for alkanes follows the general rule of CnH2n+2, where ‘n’ represents the number of carbon atoms present.

For example, methane (CH4) is the simplest alkane with one carbon atom, ethane (C2H6) has two carbon atoms, and so on. The condensed structural formula for pentane (C5H12) would be CH3(CH2)3CH3, indicating the chain of five carbon atoms with hydrogen atoms attached to each carbon. This abbreviated way of representing structural formulas is commonly used in organic chemistry.

Example of Alkanes Formula and Condensed Structure

Alkane Molecular Formula Condensed Structure
Methane CH4 CH4
Ethane C2H6 CH3CH3
Pentane C5H12 CH3(CH2)3CH3

These condensed structural formulas provide a concise representation of alkanes, allowing chemists to analyze and predict their properties and reactions. Understanding the relationship between the molecular formula and condensed structure is crucial in organic chemistry studies.

List of Alkanes and Their Structures

Alkanes are a diverse group of compounds with varying molecular formulas and structures. Here is a compilation of common alkanes along with their corresponding formulas and structures:

Alkane Formula Structure
Methane CH4
Ethane C2H6
Propane C3H8 Propane Structure
Butane C4H10
Pentane C5H12
Hexane C6H14
Heptane C7H16 Heptane Structure
Octane C8H18
Nonane C9H20
Decane C10H22

These alkanes may exhibit different arrangements of carbon atoms, resulting in either straight chains or branched chains. Visualizing the structures helps to comprehend the molecular arrangements and bonding patterns within these compounds.

Physical Properties of Alkanes

Alkanes possess a wide range of physical properties that stem from their unique molecular structure. Let’s dive into some of the notable properties that define these fascinating compounds:


One of the key features of alkanes is their nonpolar nature, which renders them hydrophobic and insoluble in water. However, they readily dissolve in organic solvents.

Boiling Point

As the molecular weight of alkanes increases, so does their boiling point. Straight-chain alkanes typically exhibit higher boiling points in comparison to their branched isomers.

Melting Point

Similar to the boiling point, the melting point of alkanes rises with an increase in molecular weight. Interestingly, even-numbered alkanes tend to have higher melting points than their odd-numbered counterparts.

These properties can be attributed to the intermolecular forces present in alkanes, with Van der Waals forces playing a significant role. The size and shape of alkane molecules influence the strength of these forces, leading to variations in their physical characteristics.

By understanding the physical properties of alkanes, we gain valuable insights into their behavior and practical applications. These diverse compounds find extensive use as fuels and serve as fundamental building blocks in the study of organic chemistry.


Alkanes are the unsung heroes of the organic compound world, providing us with an array of practical applications, primarily as fuels. From their molecular formulas and structures to their physical properties, alkanes are a fascinating subject in organic chemistry that has the power to unlock a wealth of knowledge.

Understanding the formulas and structures of alkanes is like having a secret code to their properties and behaviors. By deciphering these codes, we can predict how alkanes will react, how they will interact with other substances, and even how they will behave under different conditions.

But alkanes are not just a topic for chemistry textbooks. They form the foundation for more complex organic compounds and play an essential role in our everyday lives. Exploring the properties of alkanes opens a gateway to understanding the broader world of hydrocarbons and their vast range of practical applications beyond just fuels.

So, next time you’re filling up your car or marveling at the wonder of organic chemistry, remember the unsung heroes – alkanes. Their formulas, structures, and properties may seem abstract, but they are the building blocks of a vast and fascinating world that impacts us all.

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