$n_S = \dfrac{4,8}{32} = 0,15(mol)$
$n_{Al_2(SO_4)_3} = \dfrac{1}{3}n_S = \dfrac{0,15}{3} = 0,05(mol)$
$m_{Al_2(SO_4)_3} = 0,05.342 = 17,1(gam)$
Ta có: \(n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{3}n_S\)
\(n_S=\dfrac{4,8}{32}=0,15\left(mol\right)\Rightarrow n_{Al_2\left(SO_4\right)_3}=0,15\cdot\dfrac{1}{3}=0,05\left(mol\right)\)
\(\Rightarrow m_{Al_2\left(SO_4\right)_3}=0,05\cdot\left[27\cdot2+\left(32+16\cdot4\right)\cdot3\cdot\right]=0,05\cdot342=17,1\left(g\right)\)