Priestley's Theory Of Phlogiston
The phlogiston theory held that when a candle burned, for instance, phlogiston was transferred from the surrounding air. When air became saturated with phlogiston and could contain no more, they flame would go out. Breathing was also a way to remove phlogiston from a body. A typical test for the presence of phlogiston was to place a mouse in a container and measured how long it lived. When the air in the container would accept no more phlogiston, the mouse would die.
Antoine Lavoisier disproved the existence of phlogiston and helped to form the basis of modern chemistry using Priestley’s discovery of oxygen. Priestley founded the method of collecting gases by bubbling through water and collecting in an inverted gas jar by water displacement. …show more content…
The reaction is reversible too. Priestley found that breathing pure oxygen was beneficial but did not understand the role of oxygen in breathing (Lavoisier, who did, soon also showed that breathing produces water and carbon dioxide). Priestley also showed that plants give off oxygen in sunlight and actually discovered photosynthesis.
Priestley believed in the phlogiston theory of combustion. According to this theory, substances that could be burnt contained phlogiston which they gave off into the air during burning. Similarly, mercury would give off phlogiston when changed to ash. When Priestley heated this calx, he thought it reformed mercury by re-absorbing phlogiston from the surrounding air; this air which he collected, he therefore called ‘de-phlogisticated air’. According to this reasoning, mercury calx is mercury minus phlogiston and should, therefore, weigh less than mercury.
Antoine Lavoisier repeated Priestley’s experiment and it showed that mercury calx actually weighed more than the original piece of mercury. Lavoisier correctly deduced that when substances burned they actually combined with Priestley’s gas which he renamed oxygen . These discoveries, which revolutionized the theory of combustion, were due both to Lavoisier’s insight and his careful
Antoine Lavoisier disproved the existence of phlogiston and helped to form the basis of modern chemistry using Priestley’s discovery of oxygen. Priestley founded the method of collecting gases by bubbling through water and collecting in an inverted gas jar by water displacement. …show more content…
The reaction is reversible too. Priestley found that breathing pure oxygen was beneficial but did not understand the role of oxygen in breathing (Lavoisier, who did, soon also showed that breathing produces water and carbon dioxide). Priestley also showed that plants give off oxygen in sunlight and actually discovered photosynthesis.
Priestley believed in the phlogiston theory of combustion. According to this theory, substances that could be burnt contained phlogiston which they gave off into the air during burning. Similarly, mercury would give off phlogiston when changed to ash. When Priestley heated this calx, he thought it reformed mercury by re-absorbing phlogiston from the surrounding air; this air which he collected, he therefore called ‘de-phlogisticated air’. According to this reasoning, mercury calx is mercury minus phlogiston and should, therefore, weigh less than mercury.
Antoine Lavoisier repeated Priestley’s experiment and it showed that mercury calx actually weighed more than the original piece of mercury. Lavoisier correctly deduced that when substances burned they actually combined with Priestley’s gas which he renamed oxygen . These discoveries, which revolutionized the theory of combustion, were due both to Lavoisier’s insight and his careful