Question

Draw the condensed structural formula for each of the following: a. propionaldehyde b. butanal c. 4 -bromo- 2 -pentanone d. acetone

Short answer

a. CH3CH2CHO, b. CH3CH2CH2CHO, c. BrCH2CH2COCH3, d. CH3COCH3.

Step-by-step solution

Understand what a condensed structural formula is

A condensed structural formula is a type of chemical formula that shows how the atoms in a molecule are connected but in a more compact form. It often omits the carbon-hydrogen bonds, grouping atoms together to save space.

Draw the condensed structural formula for propionaldehyde

Propionaldehyde has three carbon atoms with an aldehyde group, which is represented as -CHO. Therefore, the condensed structural formula for propionaldehyde is CH3CH2CHO.

Draw the condensed structural formula for butanal

Butanal has four carbon atoms with an aldehyde group at the end. The condensed structural formula for butanal is CH3CH2CH2CHO.

Draw the condensed structural formula for 4-bromo-2-pentanone

4-bromo-2-pentanone has five carbon atoms, with a bromine atom on the fourth carbon and a ketone group on the second carbon. Therefore, the condensed structural formula is BrCH2CH2COCH3.

Draw the condensed structural formula for acetone

Acetone, also known as propanone, has three carbon atoms with a ketone group on the second carbon. The condensed structural formula for acetone is CH3COCH3.

Key concepts

Propionaldehyde

Let's dive into the details of propionaldehyde. This molecule is an aldehyde, which means it has a carbonyl group (C=O) located at the end of the carbon chain. An aldehyde group is represented by -CHO. Propionaldehyde, also known as propanal, has three carbon atoms in its structure. The condensed structural formula is written as CH3CH2CHO.
Aliphatic aldehydes like propionaldehyde play a fundamental role in organic chemistry as intermediates in various chemical reactions. These compounds are often used in the manufacturing of plastics, perfumes, and other chemicals. The simplicity of their structure makes them a good starting point for learning about more complex organic molecules.

Butanal

Next, we have butanal. This compound is another type of aldehyde, but this time with four carbon atoms. The aldehyde group is always at the end of the molecule, so the condensed structural formula for butanal is CH3CH2CH2CHO.
Butanal, also known as butyraldehyde, is commonly found in nature and is used in the synthesis of other chemicals, such as rubber accelerators and plasticizers. Understanding butanal is important as it forms a basis for learning about larger and more intricate molecules.

4-Bromo-2-Pentanone

Moving on to 4-bromo-2-pentanone, this molecule is more complicated. It has five carbon atoms in its chain, a bromine atom attached to the fourth carbon, and a ketone group (-CO-) on the second carbon. Its condensed structural formula is written as BrCH2CH2COCH3.
Since ketones are carbonyl compounds like aldehydes, the carbonyl group in ketones is located within the carbon chain, not at the end. The presence of the bromine atom adds another level of complexity. This type of brominated ketone can be used in various organic synthesis reactions, making it a useful compound in both industrial and laboratory settings.

Acetone

Lastly, we have acetone, which is a common ketone. It has three carbon atoms with a ketone group on the second carbon, making the condensed structural formula CH3COCH3.
Acetone is a well-known solvent used in many industries, including pharmaceuticals and cosmetics. It's also commonly used as a nail polish remover. In the world of organic chemistry, acetone is one of the simplest ketones, making it a fundamental molecule for students to understand before moving on to more complex compounds.