What are my chances of being accepted into chemical engineering at UT?
My rank is 25/297 (just short of auto admit)
My weighted GPA is 4.248
Student council, class historian, NHS, key club, high school and club soccer, debate during freshman and sophomore year, prom committee, working at best buy (15-20 hours per week)
ACT: 29 (September 2015)
English - 28
Math - 30
Reading - 32
Science - 25
SAT: 1850 (June 2015)
Math - 630
Reading - 680
Writing - 540
Your scores might be good enough to get into the college as a whole, but probably not high enough to get you into Chemical Engineering. You should consider re-taking your SAT or ACT before the application deadline. Also, make sure you have a second choice you are comfortable with as Chem E is highly competitive. Best of luck!
I’d say retake the SAT/ACT from my own experience (I’m a freshman ChemE major at UT!), though I do have a friend who was auto-admit but had ~3.2 GPA ~1700 SAT and got into McCombs. UT admissions can be weird.
Otherwise, your ECs are great! 
Good luck and hope to see you on the 40 acres!