Answer:
The mass was there all along, it was just in the air. The weight of the oxygen from the air is not weighed in the beginning, only at the end as part of the product, making it seem like there is a total mass change.
From the electric generator to electric outlets in homes
Out of the options, glass is the least fluid. The proof of this also lies in the fact that glass is the most difficult to melt out of all of the mentioned substances, and melting point gives us a rough estimate of the strength of intermolecular forces.
Just the number 2 to get the cofficients