2 IU
When a chemical reaction occurs,
a phase change takes place
the physical and chemical properties of the products are different from the reactants
the physical and chemical properties of the reactants are the same as the properties of the products
the compounds can be separated by physical means

the physical and chemical properties of the products are different from the reactants

Explanation:

A chemical reaction involves the chemical combination of two or more elements/compounds called Reactants to give one or more different elements/compounds called Products. A chemical reaction occurs in such a way that the atoms of the reactants are restructured to form product(s) that is/are entirely different from the reactants.

In a chemical reaction, the physical and chemical properties of the products differ from that of the reactants since different chemical compounds/elements are formed as products. The physical properties of a substance, which include colour, melting and boiling point etc. will differ in the reactants and products formed. Also, the chemical structure and identity of the reactants will be changed to give rise to a different chemical property in the products.

the answer is na (sodium)