Question

Which statement is correct about the theory of combustion?

1. The law of conservation of mass provided justification for the theory of combustion.
2. The theory of phlogiston provided justification for the theory of combustion.
3. • The theory of phlogiston became the theory of combustion.
4. • The law of conservation of mass became the theory of combustion.

Answer 1

B

The phlogiston theory states that as something burns, it dephlogisticates and releases stored phlogiston, which the air then absorbs. Because growing plants absorb the phlogiston, neither plant materials nor air spontaneously catch fire.

Thus, Phlogiston explained burning in a way that was totally at odds with the hypothesis of oxygen.

Phlogiston-rich substances frequently burnt in the presence of air; the fact that combustion abruptly stopped in a closed atmosphere was taken as indisputable evidence that there was a limit to the amount of phlogiston that air could carry. A metal heated in phlogisticated air couldn't form a calx or sustain life in any way. Phlogisticated air was incapable of supporting the burning of any material. When breathing, phlogiston was thought to be ejected from the body.