What is the empirical formula for 20.2% sodium, 37.6%sulfur and 42.2% oxygen

For ai it's atomic number is 13 and it's mass number is 27 how many neutrons does it have

How many liters of hydrogen gas will be produced at stp from the reaction of 7.179×10^23 atoms of magnesium with 54.219g of phosphoric acid (h3po4) the equation is 3mg + 2h3(> mg(po4)2+3h2

What are the three major branches of natural science? • earth and space science, life science, physical science •earth and space science, physical science, chemistry •physical science, life science, chemistry •life science, chemistry, physics