Now that you have selected the school of choice, there are many additional questions and preparations which need to be considered prior to and upon arrival. You will probably need to make an additional trip sometime in the summer to arrange for housing unless you apply for graduate housing, which should be available at any campus with a large graduate program.
You will also need to prepare several weeks in advance for the entrance exams usually administered the week before classes begin at most graduate programs. Tests are usually given in analytical, inorganic, organic, and physical chemistry (biochemistry tests are typically optional) to determine any potential weaknesses in your overall chemistry background. Perceived weaknesses usually result in additional course work to remove the deficiency. Hopefully this will not occur in more than one or two areas.
The first year of graduate school will primarily be occupied with course work in your selected discipline, teaching labs and problem sessions for lower division courses, and becoming acquainted with the various research groups and options available. The last item is by far the most important decision you will make with respect to completion of your degree. For the faculty research groups that you are interested in joining, you should make every effort to review their recent research publications, determine if there is sufficient support for research stipends, the average length of time required to complete the degree, and the expectations of your mentor with respect to active research time. You should talk to several graduate students at all phases of tenure within each group. These people will be the most honest with respect to attitudes towards their research topics and mentor.