# What is the percentage composition by mass of nitrogen in calcium nitrate?

%N="Mass of nitrogen in one mole of salt"/"Mass of one mole of calcium nitrate"xx100%
So we gots $C a {\left(N {O}_{3}\right)}_{2}$, whose formula mass $= 164.09 \cdot g \cdot m o {l}^{-} 1$
%N=(2xx14.01*g*mol^-1)/(164.09*g*mol^-1)~=20%