Farmer brown is planting crops in his feild s. He wants to prevent the topsoil from being blown away by the wind or washed away from by water. Which of these steps should he take. A: plow the soil many times. B: plant crops close together. C: water crops often to wet soil. D: leave the land free of crops for a long time

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.