Online access to the ACS Style Guide is available within the ACS database. See the tab at the top of screen. The library has a print edition of the ACS Guide in the Reference Collection on the first floor of the library.
The ACS Style Guide 3nd Edition
Ref. QD 8.5 .A25 2006
UW at Madison Chemistry Library
Online tips for ACS Style
University of California and Berkeley
Chemistry and Engineering Library
ACS Style Guide hints
In addition to database services like EBSCO Academic Search Premier, there are independent citation generators that allow you to plug in a source information and get it cited correctly.
The Carmichael Library has the hard copy guide to each of the major citation schemes, including the big three: MLA, APA, and Chicago. Please refer to these printed books, located on the first floor in the reference collection, if you have questions about writing and citing with these formats.