Emphasis is place on what happens rather than how or why .
Learning what happens in each reaction covered in most undergraduate organic chemistry courses requires a tremendous amount of memorization. An understanding of how reactions happen involves less material because multiple reactions proceed via similar mechanisms. Comprehending why reactions happen requires learning only a small number of core concepts that can be applied to many reactions. Therefore, learning why is much more efficient than learning only what . However, concepts required to understand why reactions occur as they do can be complicated and demand a significant investment of time to master.