Which models could be used to demonstrate the law of conservation of matter? Select all that apply. Select one or more correct answers

I'm trying if I got it right before I submit it

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.

the maximum mass of nh3 is nh3 in grams