Chem 125 Lecture 10/28/02 Projected material This material is for the exclusive use of Chem 125 students at Yale and may not be copied or distributed further. It is not readily understood without reference to notes from the lecture.

Berzelius Analysis (1) Tube 1/2” diameter (Fig 1) charged with dried powder containing ~0.5 g of organic substance, 3 g NaClO 3 (O 2 source), 50 g NaCl. (2) Neck of tube heated and drawn out (Fig 2) (3) Joined (Fig 4) to water collecting bulb (Fig 3) and CaCl 2 drying tube with rubber tubing (4) Assembled (Fig 6) so that gas (O 2, CO 2 ) that exits drying tube bubbles into bell-jar containing Hg with floating bulb (Fig 5) holding KOH (to absorb CO 2 ) and closed with permeable glove leather to keep out Hg. Wire attached to bottom so bulb can be retrieved from bell-jar. (5) Build fire in brick enclosure to heat tube slowly from near end to far. Tube wrapped with metal sheet to keep it from popping under pressure necessary to bubble through Hg when it softens at red heat.

Berzelius’s Table of atomic & molecular weights (1831) Weights

Based on O = 100 or H 2 = 1 Bars denote doubled atoms O = [15.999] (-1.0%) (-1.0) (0.4) (1.3)

Abbreviations: Dots denote O atoms = KO CrO 3 Superscripts denote numbers of atoms Benzoic should be H 10 C 14 O 3 (“acid” as anhydride) Didn’t catch on

to J.J. Berzelius Heidelberg, 17 July, 1823 “Having developed the greatest respect for you through studying your writings, I have always thought it would be my greatest good fortune to be able to practice this science under the direction of such a man, which has always been my fondest desire. Although I earlier had planned to become a physician…”

With the greatest respect F. Wöhler from Frankfurt am Main