Mount Ida College is closing at the end of the spring term and handing over its prime 74-acre Newton campus to the University of Massachusetts in exchange for the system taking on the small private college’s debt.Mount Ida’s 280 faculty and staff will be laid off after the commencement in mid-May, the school said.The private liberal arts college’s 1,450 students will be automatically accepted for fall enrollment at UMass Dartmouth — more than 50 miles away — and given a path to finish their degrees there.