Alkanes

Alkanes

Introduction

  • Alkanes are a type of hydrocarbon, which means they are compounds made up of carbon and hydrogen atoms.
  • They follow the general formula CnH2n+2.
  • This group of compounds is a series (family), each member differing by a CH2 unit.

Structure and Properties

  • Alkanes are saturated hydrocarbons meaning they only have single bonds between carbon atoms.
  • Each carbon atom forms four single bonds, and each hydrogen atom forms one single bond.
  • The relatively low reactivity of the alkanes results from the strength of the carbon–hydrogen bonds and the non-polar nature of the molecules.
  • They are less dense than water and are insoluble in water due to their non-polar nature, but these compounds readily dissolve in organic solvents.
  • The boiling point increases as the chain length (number of carbons) increases due to the increase in the size of the molecules.

Examples

  • Some examples of alkanes include: methane (CH4), ethane (C2H6), propane (C3H8) and butane (C4H10).

Reactions

  • In the presence of ultraviolet light (UV light), alkanes undergo substitution reactions with halogens, this reaction is known as halogenation.
  • Alkanes also react with oxygen in a combustion reaction to produce carbon dioxide and water. This combustion can be complete or incomplete depending on the amount of oxygen available.

Uses of Alkanes

  • Alkanes have various uses, including as fuel (like methane for heating, propane for cooking, and octane in petrol).
  • Also, they are used in petrochemical industries to make a wide variety of products such as plastics and synthetic fibres.

Environmental Impact

  • When alkanes are burned, they release carbon dioxide, which contributes to global warming.
  • Uncontrolled reactions involving alkanes can lead to fires and explosions.
  • Alkanes found in crude oil and natural gas must be extracted, which can lead to ecosystem disturbances and potential spills.

Remember, understanding the different aspects of alkanes is essential. Delving deeper into the reactions, properties, and impacts of alkanes can enhance your familiarity and comprehension of these important hydrocarbons.