Astudent adds 0.40g of sodium hydroxide to a clean, dry 250 ml beaker and leaves the beaker and leaves the beaker on the lab table. the mass of the empty beaker is 112.58g. after 24 hours, the student observes that the beaker contains a dry, solid white residue. the total mass of the beaker and its contents is 113.09g. following are three possible chemical reactions that could have occured: sodium hydroxide (solid) + carbon dioxide (gas) rightarrow sodium bicarbonate (solid) sodium hydroxide (solid) + carbon dioxide (gas) rightarrow sodium carbonate (solid) + water (gas) sodium oxide (solid) rightarrow sodium oxide (solid) + water (gas) use your knowledge of stoichiometry to determine which chemical reaction occurred. show your work, and explain your reasoning whenever needed.

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 was spontaneous.

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