Which of the following is NOT a chemical change? A. Tarnishing silver
B. Melting butter
C. Digesting food
D. Baking a cake

Melting butter

Explanation:

You can reverse the change of butter back to its original state but you can never reverse the rest back to there original state

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 correct answer to this question is 2