I'm doing an undergraduate research with a professor in my university, and he basically gave me a small project to do. This project attempts to synthesize a chemical which might be interesting to feed to a microorganism. I've been with this professor for maybe 2 months of intense meetings, work-ups, lab time, etc. In the last month we've been trying to synthesize different kind of chemical, in a group of two. This one that he gave me, I'm doing it alone, though still in early stage. Is it appropriate to ask for a recommendation letter from him? I expect to continue working with him in the coming semester.