Multiple choice Which one of the following compounds has the highest percentage of nitrogen? Ammonium nitrate Urea Calcium nitrate Ammonium chloride Reveal answer Fill a bubble to check yourself B Correct answer Explanation Urea (NH2CONH2) has a molar mass of 60 g/mol and contains 28 g of nitrogen, resulting in approximately 46.6 percent nitrogen by mass, which is higher than the other options.