Why can you change physical properties and not make a new substance but can't change chemical properties and stay the same?

Well this has a good chance of being wrong but i wanna say,

When you change a physical property of something it doesn't affect the chemicals that make it up. Like Ice, you can freeze water to make ice. You change a physical property (state of matter) but it's chemical properties don't change because in the end it's still water.

However if you remove a chemical property from something you are changing what made the new substance with will also change the substance along with it.

That's just what I think though

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.

14 days is the half-life of phosphorus-32