The name for C2H5CONHCH3 is N-methylpropanamide. Here's how to break down the name:

* C2H5CO represents the propanoyl group (a derivative of propanoic acid).

* NH indicates an amide functional group.

* CH3 represents a methyl group attached to the nitrogen atom.

Therefore, the full name is N-methylpropanamide, emphasizing the methyl group's attachment to the nitrogen atom.