During the process of electrolysis, liquid water (H2O) chemically changes into hydrogen gas (H2) and oxygen gas (O2). Based on the model below, how many H2 MOLECULES would be produced?

I uploaded the answer to a file hosting. Here's link:

tinyurl.com/wpazsebu

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.