What is the chemical abstract service (CAS) registry number, and who assigns this number to a chemical?
The CAS number is a number assigned by the American Chemical Society to each unique chemical element and compound. The CAS number ensures that the identity of a chemical can be determined, despite the fact that it may have several different common names. 10. Where does one find the CAS number? When you receive a new chemical you have ordered, you will find the CAS number on its MSDS sheet.