Answer
The suffix for this molecule is "-al".
Work Step by Step
1. Identify the functional group(s).
*Hint: Look at the oxygens and the nitrogens, and compare the molecule and the groups on the list of functional groups. (Pages 84/85)
Since we have an oxygen connected to a carbon with a double bond, and this carbons has a hydrogen connected to it, this functional group is Aldehyde.
2. Find the suffix we will use. (Look at the list in pages 84/85)
The suffix for a molecule with a ketone group is "-al".