Mr(Ca3(PO4)2)=3*40+2*31+8*16=310
W(Ca)=120/310=0.39=39%
W(P)=62/310=0.2=20%
W(O)=128/310=0.41=41%
Mr(FeNO3)=56+14+3*16=118
W(Fe)=56/118=0.47=47%
W(N)=14/118=0.12=12%
W(O)=48/118=0.41=41%
m=36 (г)
M(CuCl2)=64+2*35.5=135 (г/моль)
n=m/M=36/135=0.3 (моль)