Part I presents a quantitative-empirical outline of chemistry, esp. preparative chemistry, concerning its dominant role in today's science, its dynamics, and its methods and aims. Emphasis is laid on the poietical character of chemistry for which a methodological model is derived. Part II discusses standard distinction between science and technology, from Aristotle (whose theses are reconsidered in the light of modern sciences) to modern philosophy of technology. Against the background of results of Part I, it is argued that all these distinctions fail, because the underlying concepts of science are either out-dated, one-sided, or arbitrary. A deeper understanding of today's sciences requires, in particular, a philosopical investigation of chemistry.