Question: how to calculate the percentage of nitrogen by mass in potassium nitrate?
Answer: < br > So , the mass of a mole of potassium nitrates is 101 grams ( thirty-nine + 14 + ( 3 x sixteen ) ) . < br > Of this , nitrogen makes up 14 grams . 14 divided by 101 gives 13.87 percent , which are able rounded down to 13.9 cent .