I would rather major in pure ‘Chemistry’ because it seems more interesting but I would also like to be a Chemical Engineer and I was wondering could I be one if I took additional engineering classes?
I heard that Chemical Engineering is just Chemistry+Mechanical Engineering, so if I minor in Mechanical Engineering would I be qualified?
The two clauses in this sentence contradict each other unless you are basically saying you want to do the job that you find less interesting.
No. A minor in mechanical engineering (or chemical engineering) isn’t going to give you anywhere near the depth in topics like fluid mechanics or heat transfer (for example) that a chemical engineering degree would. It is a minor because it basically just gives you a small taste.
If you want to be a chemical engineer, study chemical engineering.