9. Melting point of a metal in an acid? a. 27500 b.2705 C c. 7250 C d. 2507CC 10. Which value represents the natural PH of water? a.7 b.14 c.d.3 11. Everything is made up of a. matter b. elements c. substance d. compound 12. A mixture is? a. a pure substance b. 2 substance that are mix together c. elements and substance . d. none of the above​