\(Ag_2O+2HNO_3\rightarrow2AgNO_3+H_2O\)
..0,1.................................0,2....................
\(3Cu+8HNO_3\rightarrow3Cu\left(NO_3\right)_2+2NO+4H_2O\)
.0,2................................0,2.......................................
Ta có : \(a=m_{Ag\left(NO\right)_3}+m_{Cu\left(NO_3\right)_2}=0,2.188+0,2.170=71,6\left(g\right)\)