How many moles of hydrogen gas would be needed to react with excess carbon dioxide to produce 30.6 moles moles of water vapor?

50.23 i believe is correct but don't quote me on that.

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.