Scheele's Elements
From WikidChem
[edit]Slide 15
This slide is self-explanatory. Scheele discovered/codiscovered seven elements: Ba, Mn, Mo, W, N, O, Cl. Note that there is an emphasis on N, O, and Cl, since understanding those three elements was the single most important detail of the Chemical Revolution.
[edit]Slide 16
Scheele burned heated Ag2CO3 to produce Ag2O + CO2. At higher temperatures (>340ºC), a second reaction took place, producing Ag + O2. He nicknamed the thus-discovered Oxygen "fire air" because it would immediately cause the fire he was using as a heat source to flare up.
The carbonate was heated in a closed vessel to allow collecting the gases, otherwise there would be no way to know that (or what) gases were generated. After the O2 was collected its influence on a flame could be tested. Scheele sent a letter to Lavoisier asking Lavoisier to use his larger and better-equipped laboratory to repeat this experiment, except without exposing the oxygen to an open flame.
