Part E The population census of a city shows that its population has grown in the last decade. This growth has
surpassed the city's ability to provide sufficient water to its people. The city is located about 10 miles from
the ocean and has a dry climate. Based on your research and the list of criteria and constraints from part
A, suggest a technology to use in this city. Defend your choice with a valid 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.