For an investigation a student poured a blue solution of CuSO4 into a beaker. The student placed a shiny silver colored strip of zinc metal in the solution and observed the changes, The student inferred that a chemical reaction occurred. What evidence supports this inference?

It is the second answer; A dark solid formed on the zinc.

Explanation:

This is the correct answer because when a solid is formed it is called a precipitate, which is commonly known as a chemical reaction.

answer; i believe that the correct answer is (a); a large rock being weathered by wind and rain;

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.