Which of the two glasses the ingredients dissolved completely class/sand or sugar

sugar

Explanation:

sand will not dissolve in water because the bond in water isn't strong enough to dissolve it.

so sand is a big no.

so the answer is the other option: which is sugar.

you need to give more information

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.