7. why is the melting point of a substance
considered a physical property, and not a
chemical property?

it is considered a physical property because it is changing its temperature and anything to do with color, odor, temp... is physical change ther for its considered a physical property.

Explanation: chemical change is when the whole chemical i-s changes such as Na(sodium) and Cl(cloride) both these chemicals separate are lowkey poisons and when you put them together it makes something not made to kill you or clean with something sorry for the long explination ;)

answer: -

reaction:

na + cl ⇌ nacl

balanced chemical equation:

na + 2cl ⇌ nacl2

sodium + clorine goes to form sodium chloride (table salt).

the product is nacl2.

and the reactants are na and cl.

(note: if you don’t know what ⇌ means, read below: -

⇌(double head arrow) means reversible reaction).

the answer to your question is c