Question: how to calculate percentage composition of urea?
Answer: Given Urea= NH2- CO- NH2 And we know that Total mass of urea = 60 Mass of nitrogen = 14 Two molecules of nitrogen= 2*14= 28 Percentage of nitrogen = Mass of Nitrogen/(Urea ) x 100 = 28/60 x 100 = 46.6% Hence Percentage of nitrogen in urea is 46% Option A is the right answer.