CHM 151 Lecture Notes - Lecture 2: Chemical Formula, Aluminium Oxide, Nonmetal
Document Summary
Aristotle (384 322 bc) held that democritus" views were impossible. But by the 1700s, things had started to change. Observations leading to the atomic view of matter. Law of conservation of mass: lavoisier, 1789 bbc documentary: chemistry, a volatile history. Law of definite proportions (law of constant composition): no matter its source, a pure compound is composed of definite or constant proportions of the elements by mass. Atoms cannot be created or destroyed in chemical reaction: compounds are formed when atoms of more than one element combine; a given compound always has the same relative number and kind of atoms. Observations leading to the nuclear model of the atom. Cathode ray tube experiments: j. j. thomson, 1897. Figure 2. 4 results: charge-to-mass ratio: e/m = 1. 76 108 c/g. Charge of a single electron, e = 1. 602 10-19 c. Electron mass: m = / = (cid:2778). (cid:2783)(cid:2777)(cid:2779) (cid:2778)(cid:2777) (cid:2778)(cid:2786) (cid:2778). (cid:2784)(cid:2783) (cid:2778)(cid:2777)(cid:2785) / = 9. 10 10-28 g.
