Given:
 2 moles HNO3
 Required:
 Grams of nitrogen
 Solution:
 3HNO2 -> HNO3 + 2NO + H2O
 Moles of N2 = (2 moles HNO3)(2 moles NO /1 mole HNO3) = 4 Moles of NO
 Molar mass of N2 = 28 g/mol
 Mass of N2 = (4 Moles of NO)(1/2 mol N2/1 mol NO)( 28g/mol)
 Mass of N2 = 56g H2O