When examining the titrations of hydrochloric acid and acetic acid with NaOH, we notice that the equivalence point of the HCl solution occurs at a pH of 7.00, while the HCH3COOH solution has an equivalence point around pH 8.72. Suppose that the hydrochloric acid solution initially contained 10 mol of HCl, while in the acetic acid solution, 10 mol of HCH3COOH were present initially. At the equivalence point, which solution contains more NaOH

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.