1. Law: Formula: A gas sample contained in a cylinder equipped with a moveable piston occupied 250 mL at a pres-sure of 9.35 atm. What would be the final pressure if the volume were increased to 560 mL at a constant temperature?

Known:

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.

it's all four options.