Question

Draw the skeletal formula for each of the following: a. 3 -methylheptane b. ethylcyclopentane c. bromocyclobutane d. 2,3 -dichlorohexane

Short answer

Draw skeletal formulas for: a) 3-methylheptane, b) ethylcyclopentane, c) bromocyclobutane, d) 2,3-dichlorohexane.

Step-by-step solution

Understanding Skeletal Formulas

A skeletal formula represents organic molecules in which carbon atoms are represented by vertices and covalent bonds by lines. Hydrogen atoms bonded to carbon are usually omitted.

Draw 3-methylheptane

1. Draw a seven-carbon chain (heptane). 2. At carbon 3, attach a methyl group (CH₃). The structure should have vertices representing carbons, with one vertex having an additional line for the methyl group at the third position.

Draw ethylcyclopentane

1. Draw a five-sided ring to represent cyclopentane. 2. Attach an ethyl group (CH₂CH₃) to any one of the carbon atoms in the ring.

Draw bromocyclobutane

1. Draw a four-sided ring to represent cyclobutane. 2. Attach a bromine atom (Br) to any one of the carbon atoms in the ring.

Draw 2,3-dichlorohexane

1. Draw a six-carbon chain (hexane). 2. At carbons 2 and 3, attach a chlorine atom (Cl) each. The structure should have vertices representing carbons, with two of these vertices having extra lines for the chlorine atoms at the 2nd and 3rd positions.

Key concepts

organic chemistry

Organic chemistry is the branch of chemistry that studies carbon-based compounds. It's called 'organic' because it was initially associated only with living organisms. However, we now know that organic compounds can be found in both living and non-living entities. Organic molecules are diverse and complex because carbon atoms can form stable bonds with many other elements, including hydrogen, oxygen, nitrogen, and others. In organic chemistry, understanding how to represent molecules using formulas, such as skeletal formulas, is crucial. Skeletal formulas simplify complex structures by focusing on the bonds between carbon atoms and the overall shape of the molecule.
Learning how to draw and interpret skeletal formulas can greatly aid in visualizing and comprehending organic molecules.

carbon chains

Carbon chains form the backbone of organic molecules. They consist of carbon atoms connected by single, double, or triple bonds. The length and branching of the carbon chain can vary, creating a variety of structures.
Molecules can be classified as straight-chain, branched-chain, or cyclic compounds depending on how the carbon atoms are arranged.

• Straight-chain: Carbons are connected in a single, continuous line.
• Branched-chain: The main carbon chain has branching side chains attached.
• Cyclic: Carbons are connected to form a ring structure.

Understanding carbon chains help us to categorize and name different organic compounds, which is fundamental in studying organic chemistry.

functional groups

Functional groups are specific groups of atoms within molecules that determine the chemical properties of those molecules. They are responsible for characteristic reactions of the molecules.
Common functional groups in organic chemistry include:

• Hydroxyl group (-OH)
• Carboxyl group (-COOH)
• Amino group (-NH₂)
• Methyl group (-CH₃), like in 3-methylheptane
• Halogens (fluorine, chlorine, bromine, iodine), like in 2,3-dichlorohexane and bromocyclobutane

These groups are often the sites of chemical reactions. Recognizing functional groups in skeletal formulas allows chemists to predict and understand the behavior of the molecules.

substituents in hydrocarbons

Substituents are atoms or groups of atoms that replace hydrogen atoms in a hydrocarbon. Hydrocarbons are compounds solely composed of hydrogen and carbon. When a substituent, such as a methyl group or a halogen like bromine, attaches to the hydrocarbon chain or ring, it forms a derivative compound.
Here’s how it works:

• Methyl group in 3-methylheptane: A CH₃ group attached to the third carbon of a heptane chain.
• Ethyl group in ethylcyclopentane: A CH₂CH₃ group attached to one of the carbons in the cyclopentane ring.
• Bromine in bromocyclobutane: A Br atom attached to one of the carbons in the cyclobutane ring.
• Chlorine in 2,3-dichlorohexane: Cl atoms attached to the second and third carbons of a hexane chain.

Knowing how to identify and work with substituents is essential for naming and understanding the properties of various organic molecules.