1) h2+o2 -> h2o

does equation 1 follow the law of conservation of mass? how can you tell?

The given equation not following the law of conservation of mass.

Explanation:

H₂ + O₂ →  H₂ O

The number of oxygen atoms on both side of equation are not equal thus mass is not conserved and this equation not follow the this law.

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

Explanation:

This law was given by French chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

2H₂ + O₂ →  2H₂ O

there are two oxygen atoms and four hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass.

mg3n2 is known as magnesium nitride

explanation:

i don't think ke is an compound