Chemistry 2e by Paul Flowers and others / 1.2 Phases and Classification of Matter

Online text: openstax.org/books/chemistry-2e/pages/1-2-phases-and-classification-of-matter

Section of Chemistry 2e by Paul Flowers, Klaus Theopold, Richard Langley and William R. Robinson. These are whole-book authors, with no separately credited chapter author. The book citation gives publication on 14 February 2019; no section revision date is inferred.

Cited passages: Chemistry 2e, §1.2: Classification of Matter, pure substances, mixtures, variable proportions, homogeneous and heterogeneous examples.