Whether it appears in print, a combination of print and electronic forms, or only in electronic form, a peer reviewed chemical journal is one in which each feature article has been examined by people with credentials in the article’s field of study before it is published.
Collections of papers from conferences may be considered peer reviewed as well, if the original presentations were “invited” or examined by experts before being accepted. Papers which appear in sources like these are considered to be as reliable as humanly possible.
In “double blind” peer review, neither the author nor the reviewers know each others’ identities. Not all peer review is double blind. As well, the literature of any profession may include journals written both for practitioners and for chemical theorists.
You can sometimes categorize a journal just by looking at its first and last few pages. Check to see if there is a page listing the Editorial Board, and see what credentials they have. If there is a page containing “instructions for authors”, it may actually say the journal is peer reviewed. If the instructions mention submitting several copies, with your name on the front page but not anywhere else in the manuscript, that is your cue that the journal uses double blind peer review.