Which of the compounds has the largest mass fraction of nitrogen? a) (NH4) 2SO4 b) N2O3 c) NH4NO3 d) NaNo3

a) Mr ((NH4) 2SO4) = Ar (N) * N (N) + Ar (H) * N (H) + Ar (S) * N (S) + Ar (O) * N (O) = 14 * 2 + 1 * 8 + 32 * 1 + 16 * 4 = 132;
ω (N in (NH4) 2SO4) = N (N in (NH4) 2SO4) * Ar (N) * 100% / Mr ((NH4) 2SO4) = 2 * 14 * 100% / 132 = 21.21%;
b) Mr (N2O3) = Ar (N) * N (N) + Ar (O) * N (O) = 14 * 2 + 16 * 3 = 76;
ω (N in N2O3) = N (N in N2O3) * Ar (N) * 100% / Mr (N2O3) = 2 * 14 * 100% / 76 = 36.84%;
c) Mr (NH4NO3) = Ar (N) * N (N) + Ar (H) * N (H) + Ar (N) * N (N) + Ar (O) * N (O) = 14 * 1 + 1 * 4 + 14 * 1 + 16 * 3 = 80;
ω (N in NH4NO3) = N (N in NH4NO3) * Ar (N) * 100% / Mr (NH4NO3) = 2 * 14 * 100% / 80 = 35%;
d) Mr (NaNO3) = Ar (Na) * N (Na) + Ar (N) * N (N) + Ar (O) * N (O) = 23 * 1 + 14 * 1 + 16 * 3 = 85
ω (N in NaNO3) = N (N in NaNO3) * Ar (N) * 100% / Mr (NaNO3) = 1 * 14 * 100% / 85 = 16.47%.

Answer: Option b).