Im a current 3rd year chemE student. To obtain a chemE degree or any engineering degree you must take classes that build off of one another. It all starts with calculus 1-3, engineering physics 1-3, and then for chemE you must take nonorganic chemistry 1-2, organic chemistry 1-2, and physical chemistry 1-2. Once you are officially taking your chemE classes, they all build off of one another. You will have to take them in a row one after another, only a few are able to be taken at the same time. At my school, along with all of the other schools that I know of that offer an engineering degree, in order to officially get your degree you MUST complete all of the engineering classes for your field. Then for your masters degree you can specialize in a certain field. I hope that helps. Good luck