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what is the reaction to show the bond cleavage

Fast and slow free-radical recombination reactions in thermal breakdown. As thermally induced bond-cleavage reactions and the depolymerisation of coals accelerate above 350–375°C, the more reactive of the free radicals have greater potential to undergo either retrogressive or quenching (cappin

Explanation:

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.

- decrease the number of plants and animals living in the water.