IOWA CITY — The University of Iowa has services and programming to help black and Latino students feel welcome. But a lot of those students don’t know about the programs, minority students preparing to graduate this month said.Meantime, these students struggle to exist in a predominantly white campus, they said.“When you think of universities, you think of white spaces,” Kimberly Chexnayder, a senior from Kansas City, Mo., said during a forum IowaWatch organized to talk about the concerns Thursday night.