At one time, a lot of the liberal arts colleges especially thought that a person didn't get a well-rounded education if all he or she took was science courses. There was also a feeling that a purely technical education produced a purely technical person without the skills required to be a good communicator or manager. Bachelor of Arts programs in sciences were designed to provide a strong technical background in a particular field, but still allow sufficient room for other, non-technical coursework. Most of the time this is done using electives - in chemistry, for example, both BA and BS degree chemists would have the same core chemistry curriculum and the same general English, history, and basic math requirements, but the BA student would be getting electives in things like arts, humanities, management, or languages, and the BS student would be getting electives in the maths and sciences.
This allowed for career options like management in technical fields, editing technical journals, technical writing, science advisor to political figures, teaching in the sciences, and other fields where scientific results were not necessarily the only, or even the major, determinant of success.
When it comes to looking for a job, as a new chemist with no experience and a fresh undergraduate degree, you need to demonstrate to your employer how whatever coursework you took is going to make you the best candidate for the job. If you get a BS degree, emphasize all the extra science and math that you took and show how it will apply to the job you expect to get. If you get a BA degree, emphasize the extra communications, management skills, acting lessons, or whatever you took, and show how it makes you a better candidate. If you can define the terms under which they are considering your BA or BS early in your cover letter, then there will be less chance that they will automatically categorize you as soon as they see the letters.