the volume of a container increases, the pressure inside of it decreases. Explain why the pressure goes down, in terms of the behavior of the gas particles .

the answer is 75.0%.

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.  

it has both hydrogen and oxygen