10. What is a ketone? An aldehyde? 11. Is glucose a ketone or an aldehyde?

10. **Ketone**: A ketone is a type of organic compound characterized by the presence of a carbonyl group (C=O) where the carbon atom of the carbonyl is bonded to two other carbon atoms. The general formula for ketones is \( R_2C=O \), where \( R \) represents hydrocarbon groups. Ketones are commonly found in various biological and industrial processes. **Aldehyde**: An aldehyde is another type of organic compound that also contains a carbonyl group, but in this case, the carbonyl carbon is bonded to at least one hydrogen atom and one carbon atom. The general formula for aldehydes is \( RCHO \), where \( R \) is a hydrocarbon group. Aldehydes are often found in natural substances and are important in various chemical reactions. 11. **Glucose**: Glucose is classified as an aldehyde because it contains an aldehyde functional group. Specifically, it has a carbonyl group at the first carbon atom in its structure, which is characteristic of aldehydes. In its cyclic form, glucose can also exist as a hemiacetal, but in its open-chain form, it is clearly an aldehyde.