What has to be equal on both sides of the chemical reaction in order for it to be balanced? total number of molecules

sum of the subscripts

total number of atoms

sum of the coefficients

total number of atoms

Explanation:

if you have 6 carbon atoms in reactants then you should have 6 carbon atoms in products.

Answer is in the photo. I can't attach it here, but I've uploaded it to a file hosting. link below! Good Luck!

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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.