普利斯特里( Joseph Priestly),英 氧气的发现者国 舍勒( Carl wilhelm scheele),瑞典 Antoine Lavoisier),法国 freed thinking from phlogiston theory PRIESTLY'S DEPHLOGISTICATED AIR Red mercury calx is heated and the effluent collected over water The gas supports combustion better than air. 2HgO-△2Hg+O,个 from air, inc- rizes he has removed the phlogiston Preistly the hlogiston and support combustion Experiment is QUALITA 2KNO-A>2KNO2+O,个 LAVIOSIER'S OXYGEN Mercury is heated until a red calx forms. The volume of air in the cylinder decreases as the water rises. When calx stops forming heating is stopped Mercury plus calx has gained exactly the same weight as the cylinder has lost 2Hg+O2-2HgO Remaining air does not support combustion Calx is now heated as in P experiment. Air given off weighed the same as hGo 2Hg+O the weight lost previously and supported combustion Experiment is QUANTITATIVE氧气的发现者 • 普利斯特里(Joseph Priestly) ，英 国 • 舍勒(Carl Wilhelm Scheele)，瑞典 • 拉瓦锡(Antoine Lavoisier)，法国 2 2 2 HgO Hg O ⎯⎯→ +   3 2 2 2 2 KNO KNO O ⎯⎯→ +   2 2 2 2 2 2 Hg O HgO HgO Hg O   + ⎯⎯→ ⎯⎯→ + 