Adding a Chemistry Major requires a signature from Dr. Christine Pastorek, Head Advisor of the Chemistry department. 

Obtain the form entitled  "Change of Undergraduate Academic Program" This form can also be obtained from the office of your college or school or the Registrar's office. Fill in the appropriate information (name, 520  code for chemistry, etc.). 

Email Dr. Pastorek to arrange an advising appointment.  Make sure to bring your form.