Black students are plentiful at most HBCUs, but most HBCUs do not have much ethnic diversity of non-Black students.
Chemical engineering can be looked up at APS
Chemistry can be looked up at ACS-Approved Chemistry Programs - American Chemical Society
HBCUs with both majors include Florida A&M, Hampton, Howard, and NC A&T as well as Tuskegee.
Among California publics, those with chemical engineering (the less common of the two majors) include CPP, CSULB, SJSU, UCB, UCD, UCI, UCLA, UCR, UCSD, UCSB. Chemical engineering has historically been a less selective major at CPP, according to CPP Freshmen Student Profile: Multifactor Admission . It is somewhat more selective at SJSU, according to Freshmen Impaction Results | Admissions . At UCs, engineering tends to be more competitive for admission, although Freshman admission by discipline | University of California does not break it down to specific engineering majors.
For CSUs and UCs, be sure to recalculate HS GPA. GPA Calculator for the University of California – RogerHub is a handy calculator. Most UC web sites use the weighted-capped HS GPA. CSU also uses the weighted-capped GPA, except that any semester college courses count double (as if they were two semesters of courses and grades each).