Yes, but not with all question words. It makes it more general - "why [do people, in general] study chemistry?" - what is the general point of studying chemistry?
Similarly "Which refrigerator [would be a good one to buy]?" [There's a magazine just called 'Which?' - about consumer choices. And there have been lots of similar titles: Which computer?, What car?...
But "When" and "How" need a to-infinitive, and do not give the general sense:
He had to visit his aunt, but when to go?
He knew he had to get out, but how to avoid the guards?
Hmm... Maybe these ones with a to-infinitive are completely different. Perhaps some other teacher could help me out...
Student or Learner