Dalam 500 kg urea (CO(NH2)2 terkandung unsur nitrogen sebesar...

(CO(NH₂)₂) = CON₂H₄

Mr CON₂H₄ = 1 × Ar C + 1 × Ar O + 2 × Ar N + 4 × Ar H
Mr CON₂H₄ = 1 × 12 + 1 × 16 + 2 × 14 + 4 × 1
Mr CON₂H₄ = 12 + 16 + 28 + 4
Mr CON₂H₄ = 60

m N : m CON₂H₄ = 14 : 60
m N = 14/60 × 50 kg
m N = 116,6 kg