Final answer:
Amides have a carbonyl group bonded to a nitrogen with hydrogens, while N-substituted amides have one or more hydrogen atoms replaced by hydrocarbon groups.
Step-by-step explanation:
Distinguishing Between Amides and N-Substituted Amides
Amides are organic compounds characterized by the presence of a carbonyl group (C=O) bonded to a nitrogen atom. The simplest form of an amide has hydrogen atoms attached directly to this nitrogen. However, an N-substituted amide is a more complex molecule where one or more hydrogen atoms attached to the nitrogen are replaced by hydrocarbon groups or alkyl groups. This means an amide has the general structure R-C(=O)-NH2, whereas an N-substituted amide's general structure would be R-C(=O)-NRR', where R and R' can be hydrogen or hydrocarbon groups.