Most of what's in these handouts, and much, much else, is just in their heads--at least the part that's relevant to their field, obviously an organic chemist is going to have slightly different things memorized than a geochemist. For things that you have to look up, for decades the first thing you reach for would be the CRC Handbook https://en.wikipedia.org/wiki/CRC_Handbook_of_Chemistry_and_... although it's on the web now https://hbcp.chemnetbase.com/contents/ContentsSearch.xhtml?d... as well as other reference materials.