Question

What is the percent of nitrogen (N) by mass

in a 55.0 g sample of Fe(NO3)3? The molar
mass of Fe(NO3)3 is 241.86 g/mol.

Answer 1

Molar Mass of Nitrogen in Fe(NO₃)₃ :

Mr N = 3 • (14.01 g/mol)

Mr N = 42.03 g/mol

Percent of Nitrogen in Fe(NO₃)₃ :

% N = (Mr N / Mr Fe(NO₃)₃) • 100%

% N = (42.03 / 241.86) • 100%

% N = 17.38 %