# How do you find the percent composition (by mass) of each element in iron(II) nitrate?

May 16, 2017

"%composition (m/m)"="Mass of element in 1 mol of compound"/"Molar mass of compound"xx100%.

#### Explanation:

For $F e {\left(N {O}_{3}\right)}_{2}$............

%Fe=(55.85*g*mol^-1)/(179.87*g*mol^-1)xx100%=31.0%

%N=(2xx14.01*g*mol^-1)/(179.87*g*mol^-1)xx.............=??

%O=(6xx16.00*g*mol^-1)/(179.87*g*mol^-1)xx.............=??

Should the individual percentages sum up to 100%? Why?