Why is it difficult to prove the law when gas is produced ?

If you were referring to the law of conservation of mass when a gas is produced it is difficult to prove that because it would be virtually impossible to measure the mass of gas in a container as it would probably be similar and density the air

Atomicity occurs to prevent updates of the database occurring only partially, which can cause greater problems than rejecting the whole series outright.some are monatomic, diatomic, triatomic etc because it shows the number of atoms. for example, monatomic means it contains only one atom.

Crust,mantle,core,earth