Answer:
1) 36.70 %; 2) 39.05 %; 3)17.75 %
Step-by-step explanation:
% of element = Mass of element/mass of compound × 100 %
1) N in Mg(CN)₂
The masses of each element are:
1Mg = 1 × 24.30 = 24.30 u
2C = 2 × 12.01 = 24.02 u
2N = 2 × 14.01 = 28.02 u
TOTAL = 76.34 u
% N = 28.02/76.34 × 100 %
= 36.70 %
2) K in KHCO₃
The masses of each element are:
1K = 1 × 39.10 = 39.10 u
1H = 1 × 1.008 = 1.008 u
1C = 1 × 12.01 = 2.01 u
3O = 3 × 16.00 = 48.00 u
TOTAL = 100.12 u
% N = 39.10/100.12 × 100 %
= 39.05 %
3) H in NH₃
The masses of each element are:
1N = 1 × 14.01 = 14.01 u
3H = 3 × 1.008 = 3.024 u
TOTAL = 17.03 u
% N = 3.024/17.03 × 100 %
= 17.75 %
