Calculate the percentage of nitrogen in NH2CONH2.

ANSWER:

Molar mass of urea = 14+2+12+16+14+2 = 60 g/mol.

Mass of N in the molecule = 28 g/mol.

% of N = Mass of N / Molar Mass ✕ 100

= 28 gmol^-1 / 60 gmol^-1 ✕ 100

= 46.67% Ans

(Ref. An Insight Into Objective Chemsitry-11, Ch-01, Q. No. 32)