I am planning to apply for Fall 2018 for CS.
Cornell’s website states that
"At a minimum, transfer applicants should be sure that they have taken college-level courses in calculus, chemistry, physics (calculus-based), computer programming, and writing and have a minimum GPA of 3.0 "
However I have already taken a biology course (instead of chem) which would satisfy a general ed requirement at my current school.
How would a missed chem prereq hurt my chances?
If it’s a pre-req for CS, there’s no getting around taking it, unfortunately. Believe me, I learned the hard way! Cornell will require you to take it the summer before or while you are there, which I’d imagine when you are starting your heavier courses, you might not want to have chem on your schedule too, especially if it’s not your thing.
For me, it’ll wind up being a pesky Freshman Writing Seminar, an extra biology course, and/or potentially calc II 
I don’t mind any of them particularly, but them being added on to an already loaded science-heavy curriculum, it’s a little bothersome!
If you took the AP Chem exam and did well, they might honor those credits. I’m not sure about CS, but I know for CALS and Hum EC they take it.
i definitely have no problem taking chem or whatever else at the university if I am somehow accepted, but as long as its not a deal breaker for their admissions office because it is listed as a “minimum requirement”. But yea I agree it would be a little bothersome to take those classes along with the other heavier courseload