Urea is a very important nitrogenous fertilizer. Its formula is CON₂H₄. Calculate the percentage of carbon in urea.

(C= 12, O = 16, N = 14 and H = 1)

Relative molecular mass of CON₂H₄
   = 12 + 16 + 2 x 14 + 4 x 1
   = 12 + 16 + 28 + 4
   = 60 amu

Wt. of C in CON₂H₄ = 12 g

% of C = $\dfrac{\text{Wt. of C}}{\text{Total Wt. of CON}$2\text{H}4}\times 100

= $\dfrac{12}{60}$ x 100 = 20%

∴ Carbon in Urea is 20%