What is the mass percent of nitrogen in lead (ii) nitrate (pb(no3)2)?

In order to calculate the mass percent of nitrogen in Pb(NO3)2, first, list the molar mass of all elements. 

Pb = 207.2 g/mol
N = 14 g/mol
O = 16 g/mol

Then, multiply each element to the number of each atom in the compound to get the mass contribution of each element, in this case:

Pb = (207.2 x 1) = 207.2
N = (14 x 2) = 28
O = (16 x 6) = 96

Add the resulting products to obtain the total molecular mass of the compound. This is equal to 331.2 g/mol. Finally, to get the mass percent of nitrogen, divide its mass contribution by the total molecular mass, as in, (28/331.2) x 100%. Thus, the mass percent of nitrogen in Pb(NO3)2 is 8.45%.  
 

Ithink the answer is 56.