Question

Draw the condensed structural formula for each of the following: a. acetaldehyde b. 2 -pentanone c. butyl methyl ketone d. 3 -methylpentanal

Short answer

a. CH₃CHO b. CH₃CO(CH₂)₂CH₃ c. CH₃CO(CH₂)₃CH₃ d. CH₃CH₂CH(CH₃)CH₂CHO

Step-by-step solution

- Understand Condensed Structural Formulas

Condensed structural formulas express the connectivity of atoms in a molecule without showing all individual bonds explicitly. Begin by identifying the molecular structure for each compound.

- Draw Acetaldehyde

Acetaldehyde has the formula CH₃CHO. The carbonyl (C=O) group is bonded to one hydrogen atom and one methyl group.

- Draw 2-Pentanone

2-Pentanone has the formula CH₃CO(CH₂)₂CH₃. The carbonyl group (C=O) is positioned at the second carbon of the pentane chain.

- Draw Butyl Methyl Ketone

Butyl Methyl Ketone, also known as 2-hexanone, has the formula CH₃CO(CH₂)₃CH₃. The carbonyl (C=O) is bonded to a methyl group and a butyl group.

- Draw 3-Methylpentanal

3-Methylpentanal has the formula CH₃CH₂CH(CH₃)CH₂CHO. The aldehyde group (CHO) is at the end of the chain, with a methyl group attached to the third carbon of the pentanal chain.

Key concepts

organic compounds

Organic compounds are chemical compounds primarily made of carbon and hydrogen atoms. They often contain other elements such as oxygen, nitrogen, sulfur, and halogens. The presence of carbon atoms allows organic compounds to form a variety of structures like chains and rings, leading to a vast number of different compounds.
Organic compounds are fundamental in both chemistry and biology. They are crucial in the structure of cells and functioning of organisms. Everyday materials like plastics, medicines, and fuels are organic compounds.
Understanding organic compounds is essential for recognizing different molecular structures and their properties.

functional groups

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. They play a significant role in determining the properties and behaviors of organic compounds.
Some common functional groups include:

• Alcohols (-OH)
• Aldehydes (-CHO)
• Ketones (C=O)
• Carboxylic acids (-COOH)
• Amine (-NH₂)

Functional groups help classify organic compounds and predict their reactions. For example, in the exercise above, identifying aldehyde and ketone groups helps understand the molecular structures of acetaldehyde, 2-pentanone, butyl methyl ketone, and 3-methylpentanal.

carbonyl compounds

Carbonyl compounds contain a carbon-oxygen double bond (C=O). They are categorized mainly into two groups: aldehydes and ketones.

• Aldehydes have at least one hydrogen atom bonded to the carbonyl carbon (e.g., acetaldehyde).
• Ketones have two carbon atoms bonded to the carbonyl carbon (e.g., 2-pentanone).

The carbonyl group is highly reactive because of the polar nature of the C=O bond.
This reactivity makes carbonyl compounds key intermediates in various chemical reactions. In the exercise above, identifying the position of the carbonyl group helps in drawing the correct condensed structural formulas.

structural formulas

Structural formulas represent the arrangement of atoms within a molecule. They can be shown in different forms, such as full structural formulas, semi-structural formulas, and condensed structural formulas.
Condensed structural formulas simplify the representation by omitting some or all of the bonds, making them shorter and easier to read for complex molecules. For instance, acetaldehyde is written as CH₃CHO in condensed form, showing the connectivity without drawing out each bond.
Being familiar with different structural formulas enables chemists to communicate complex molecular structures more efficiently. This understanding is essential for solving exercises involving the drawing of various organic molecules based on their functional groups and connectivity.