What is the phlogiston theory?
Q: What is the phlogiston theory?
A: It is a theory that suggests there was a fire-like element called phlogiston inside combustible bodies which was released during combustion.
Q: How was the phlogiston theory formed?
A: The theory was first suggested in 1667 by Johann Joachim Becher.
Q: What was the effect of combustion on the phlogiston?
A: When the substances burned, the phlogiston escaped leaving a solid ash called calx.
Q: Why did the phlogiston theory explain why the mass after burning fuels was less than the original mass?
A: The theory explained that phlogiston escaped during combustion, which reduced the mass of the substance.
Q: Was the phlogiston theory proven to be true?
A: No, the phlogiston theory was dismissed at the end of the 18th century following further experiments by Antoine Lavoisier and others. Careful experiments that measured the masses of gasses showed that the phlogiston theory was wrong.
Q: Did some scientists continue to believe in phlogiston even after it was proven to be incorrect?
A: Yes, some scientists continued to believe in phlogiston as an explanation for the heat and light given off in combustion reactions.
Q: What do we understand now about the heat and light given off in combustion reactions?
A: Nowadays, we see this as evidence of the transfer of energy to the surroundings.
