In a mixture of gases exerting a total pressure of 2.50 atm, carbon dioxide has a mole fraction of 0.450. What is the partial pressure of carbon dioxide?

it is b that is the answer.

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.