Question

Write the general formula of each of the following types of compounds, using \(R\) to denote an organic group: (a) ether; (b) ketone; (c) ester; (d) amide.

Short answer

The general formulas are: (a) Ether: R-O-R', (b) Ketone: R-CO-R', (c) Ester: R-COO-R', (d) Amide: R-CONH2 or R-CONH-R' or R-CONR'R''.

Step-by-step solution

General Formula for Ether

An ether is characterized by an oxygen atom connected to two organic groups. The general formula for an ether can be written as R-O-R', where R and R' are the organic groups which may be the same or different.

General Formula for Ketone

A ketone has a carbonyl group (a carbon double-bonded to an oxygen) flanked by two organic groups. The general formula for a ketone is R-CO-R', with R and R' being the organic groups.

General Formula for Ester

An ester is formed from an organic acid and an alcohol. It has a carbonyl group adjacent to an ether linkage. The general formula for an ester is R-COO-R', where R is the organic group derived from the acid and R' is from the alcohol.

General Formula for Amide

An amide contains a carbonyl group attached to a nitrogen atom. The general formula for an amide is R-CONH2 or R-CONH-R' or R-CONR'R'', depending on the number of organic groups attached to the nitrogen.

Key concepts

Ether Formula

Ethers are a class of organic compounds featuring an oxygen atom linked to two alkyl or aryl groups. The simplicity of the ether formula, represented as R-O-R', belies the compound's versatility. These groups, denoted by R and R', can be either identical or different, leading to a wide array of possible ethers. For instance, if R and R' are both methyl groups, the result is dimethyl ether, a common ether variant.

Ethers are known for their relatively low reactivity, which explains their frequent use as solvents in various chemical reactions. They can also be found in applications as diverse as pharmaceuticals, fragrances, and as starting materials for synthesis of other compounds.

Ketone Structure

Ketones are characterized by their distinct structural feature, a carbonyl group (C=O) bonded to two carbon-containing groups, R and R'. This structure is encapsulated in the general formula R-CO-R', where R and R' represent the organic groups connected to the carbonyl carbon. While these groups can be identical, creating symmetrical ketones, they're often different.

The properties of a ketone, including its reactivity and boiling point, are influenced heavily by the nature of the R and R' groups. Ketones play a critical role in the biochemistry of living organisms and are also industrially important, notably in the production of materials like solvents and polymers.

Ester General Formula

Esters are pleasingly fragrant compounds often responsible for the aromas of fruits and flowers. Structurally, they contain a carbonyl group adjacent to an oxygen atom that's also bonded to an organic group represented as R-COO-R'. The 'R' is typically derived from an acid, whereas the 'R'' originates from an alcohol.

Practical applications of esters range from manufacturing plastics and solvents to serving as flavoring and fragrance agents. Due to the esterification reaction that forms them, esters are frequently studied in organic chemistry courses, illustrating principles of functional group transformations and reaction mechanisms.

Amide Chemical Formula

Amides are found in a vast array of natural and synthetic compounds, including proteins, plastics, and pharmaceuticals. They are noted for the presence of a carbonyl group linked to a nitrogen atom. The general formula for an amide is diverse, represented by R-CONH2 for simple amides or R-CONH-R' and R-CONR'R'' for substituted amides, where 'R' groups are bound to the nitrogen.

The amide bond is key to the structure of proteins, lending its name to the peptide bond, while synthetic amides like polyamides, which include nylons, are vital to the textile industry. Amides, due to their strong hydrogen bonding, generally exhibit high melting and boiling points, as well as resistance to chemical breakdown.