When mrs. green describes the physical properties of matter she said that physical properties often concern changes in state. one physical property that does not describe a change in state is

Properties of matter can be broadly classified into two categories:

-Physical properties, these usually involve a change in the state of matter

-Chemical properties. these involve a change in the chemical composition of matter.

Now, physical properties can be further classified as:

Extensive: these depend on the amount of the substance, eg: mass, volume  

Intensive: these do not depend on the amount of the substance eg: density, color, melting point, boiling point

A physical property that does not describe a change in state is color. For example: copper sulfate is a compound which is a blue in color. Thus, color provides information which describes the appearance of matter. In contrast, properties like melting or boiling point suggests a change in the state of the substance.

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.

a corroding iron, if that's one of your choices