CnH2n-2

Definition

CnH2n-2 is a general formula that represents a class of unsaturated hydrocarbons, specifically alkenes, where 'n' represents the number of carbon atoms in the molecule. These hydrocarbons have a double bond between two carbon atoms, resulting in a lower hydrogen-to-carbon ratio compared to saturated hydrocarbons.

5 Must Know Facts For Your Next Test

1. The general formula CnH2n-2 represents a class of alkenes, which are unsaturated hydrocarbons with one carbon-carbon double bond.
2. The 'n' in the formula represents the number of carbon atoms in the molecule, and the '2n-2' term accounts for the lower hydrogen-to-carbon ratio due to the presence of the double bond.
3. Alkenes with the CnH2n-2 formula have a degree of unsaturation of 1, meaning they contain one carbon-carbon double bond.
4. Compounds with the CnH2n-2 formula are more reactive than their saturated counterparts (alkanes) due to the presence of the carbon-carbon double bond.
5. The CnH2n-2 formula is commonly used to describe the structure and properties of various alkenes, such as ethene (C2H4), propene (C3H6), and butene (C4H8).

Review Questions

• Explain the significance of the CnH2n-2 formula in the context of hydrocarbons.
  • The CnH2n-2 formula is significant in the context of hydrocarbons because it represents a class of unsaturated hydrocarbons known as alkenes. These molecules have a carbon-carbon double bond, which results in a lower hydrogen-to-carbon ratio compared to saturated hydrocarbons (alkanes). The presence of the double bond makes alkenes more reactive and gives them unique chemical and physical properties that are important in various chemical processes and applications.
• Describe how the degree of unsaturation is related to the CnH2n-2 formula.
  • The degree of unsaturation, which is a measure of the number of carbon-carbon double or triple bonds in a molecule, is directly related to the CnH2n-2 formula. Compounds with the CnH2n-2 formula have a degree of unsaturation of 1, meaning they contain one carbon-carbon double bond. This lower hydrogen-to-carbon ratio, compared to saturated hydrocarbons, is a defining characteristic of the CnH2n-2 class of compounds and contributes to their unique chemical and physical properties.
• Analyze the reactivity of compounds with the CnH2n-2 formula compared to their saturated counterparts.
  • Compounds with the CnH2n-2 formula, which represent alkenes, are generally more reactive than their saturated counterparts (alkanes) due to the presence of the carbon-carbon double bond. The double bond provides a region of higher electron density, making alkenes susceptible to electrophilic addition reactions. This increased reactivity allows alkenes to participate in a variety of chemical transformations, such as hydrogenation, halogenation, and polymerization, which are important in various industrial and organic chemistry applications. The reactivity of CnH2n-2 compounds is a key factor that distinguishes them from the more stable and less reactive alkanes.

Related terms

Alkenes: Unsaturated hydrocarbons with at least one carbon-carbon double bond.

Unsaturated Hydrocarbons: Hydrocarbons that contain at least one carbon-carbon double or triple bond, resulting in a lower hydrogen-to-carbon ratio than saturated hydrocarbons.

Degree of Unsaturation: A measure of the number of carbon-carbon double or triple bonds in a molecule, which determines its level of unsaturation.