Chem 1021-1022 has a new item on Reserve. It is a Custom Solutions Manual.
The manual is divided into sections. The call number includes the chapter numbers to help the students get the section of the manual needed.
For example, Chem 1021 uses QD33.2 .S55 Chpt. 1-7 and QD33.2 .S55 Chpt.8-12/15.
Take a look at the course page for each class to become familiar with the call numbering.