Calculate the mass fraction of the elements: a) ammonium nitrate NH4NO3 b) urea CO (NH2) 2

a) ω (N in NH4NO3) = N (N) * Ar (N) * 100% / Mr (NH4NO3) = 2 * 14 * 100% / 80 = 35%;
ω (H in NH4NO3) = N (H) * Ar (H) * 100% / Mr (NH4NO3) = 4 * 1 * 100% / 80 = 5%;
ω (O in NH4NO3) = 100% – ω (N) – ω (H) = 100% – 35% – 5% = 60%.
b) ω (C in CO (NH2) 2) = N (C) * Ar (C) * 100% / Mr (CO (NH2) 2) = 1 * 12 * 100% / 60 = 20%;
ω (O in CO (NH2) 2) = N (O) * Ar (O) * 100% / Mr (CO (NH2) 2) = 1 * 16 * 100% / 60 = 26.67%;
ω (N in CO (NH2) 2) = N (N) * Ar (N) * 100% / Mr (CO (NH2) 2) = 2 * 14 * 100% / 60 = 46.67%;
ω (H in CO (NH2) 2) = 100% – ω (C) – ω (O) – ω (N) = 100% – 20% – 26.67% – 46.67% = 6.66%.