Draw up the formula for the sodium compound with nitrogen and calculate the mass fractions of elements in it

Given:
Na3N

To find:
ω (Na in Na3N) -?
ω (N in Na3N) -?

Solution:
1) Mr (Na3N) = Ar (Na) * N (Na) + Ar (N) * N (N) = 23 * 3 + 14 * 1 = 83;
2) ω (Na in Na3N) = N (Na in Na3N) * Ar (Na) * 100% / Mr (Na3N) = 3 * 23 * 100% / 83 = 83.13%;
3) ω (N in Na3N) = 100% – ω (Na in Na3N) = 100% – 83.13% = 16.87%.

Answer: Mass fraction of Na in Na3N is 83.13%; N in Na3N – 16.87%.