I would think your undergraduate handbook (or equivalent) would give course titles and descriptions, which would give you an idea of what you'd be studying in each major.
In my experience, chemical engineers tend to focus on process variables (heat and mass transfer, energy balance, etc.). They design reactors and processes for optimized efficiency and performance. Material engineers study properties of materials and how to improve them (and sometimes new methods to make them). There will be overlap between the two disciplines, particularly in thermodynamics and kinetics of chemical reactions.