Question re proffesionalism

I saw a listing for a prn position, but the details are very vague. Is it ok to email a few questions, or should I just go ahead an email my resume and cover letter and ask the questions later on? An informal email just seems unprofessional, but I am curious to the answers before applying. Advice?
Send your resume' and ask questions IF you get called for an interview.

Thank you! It just seemed inappropriate to send an informal email you know what I mean?