# Internal combustion...

Noticed that when u burn something its mass decreased like if u place a fuse on a scale and burn it, its mass decreases. But Antoine Lavoiser determined that if all the particles in the gas collected, like if you burn the fuse inside a closed bottle the mass stays the same...i don't understand this concept n how it works. Please help me and thanks in advance :)

mfb
Mentor
Some fraction of the initial solid matter gets converted to gas*. If you let the gas escape, the remaining mass is lower than the initial mass. If you keep all gas in the system, you see that the overall mass stayed the same.
I don't understand the problem.

*it also changes its composition, that is the point of combustion, but it is not relevant here.

Some fraction of the initial solid matter gets converted to gas*. If you let the gas escape, the remaining mass is lower than the initial mass. If you keep all gas in the system, you see that the overall mass stayed the same.
I don't understand the problem.

*it also changes its composition, that is the point of combustion, but it is not relevant here.
My question was just why the mass stayed the same and you answered it...thanks