There are nine alkane constitutional isomers with the molecular formula C₇H₁₆. Draw them.

Verified step by step guidance

1. Start by drawing the longest possible carbon chain for C₇H₁₆, which is heptane (7 carbon atoms in a straight chain).
2. Next, draw a 6-carbon chain (hexane) and add a methyl group (CH₃) at different positions to create isomers. Consider positions 2, 3, and 4 for the methyl group to avoid duplicates due to symmetry.
3. Then, draw a 5-carbon chain (pentane) and add two methyl groups. Place them at different positions such as 2,2-dimethylpentane, 2,3-dimethylpentane, and 2,4-dimethylpentane.
4. Draw a 5-carbon chain and add an ethyl group (C₂H₅) at different positions, such as 3-ethylpentane.
5. Finally, draw a 4-carbon chain (butane) and add three methyl groups at various positions, such as 2,2,3-trimethylbutane.

Key Concepts

Alkanes

Alkanes are saturated hydrocarbons consisting only of carbon (C) and hydrogen (H) atoms, connected by single bonds. They follow the general formula CnH2n+2, where n is the number of carbon atoms. Alkanes are characterized by their relatively low reactivity and are commonly found in natural gas and petroleum.

Constitutional Isomers

Constitutional isomers are compounds that have the same molecular formula but differ in the connectivity of their atoms. This means that the arrangement of atoms in the molecule varies, leading to different structural forms. For alkanes, this results in various branched and unbranched structures, which can significantly affect their physical and chemical properties.

Drawing Structural Formulas

Drawing structural formulas involves representing the arrangement of atoms in a molecule, including bonds between them. For alkanes, this includes depicting the carbon backbone and the hydrogen atoms attached to each carbon. Understanding how to visualize and draw these structures is essential for identifying and differentiating between the various constitutional isomers.