a) Mg + 2AgNO3 → Mg(NO3)2 + 2Ag↓
b) \(n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)\)
Theo PT: \(n_{AgNO_3}=2n_{Mg}=2\times0,2=0,4\left(mol\right)\)
\(\Rightarrow m_{AgNO_3}=0,4\times170=68\left(g\right)\)
Theo PT: \(n_{Mg\left(NO_3\right)_2}=n_{Mg}=0,2\left(mol\right)\)
\(\Rightarrow m_{Mg\left(NO_3\right)_2}=0,2\times148=29,6\left(g\right)\)