nAl = 2.7/27 = 0.1 (mol)
nH2SO4 = 9.8/98 = 0.1 (mol)
2Al + 3H2SO4 => Al2(SO4)3 + 3H2
1/15........0.1.............1/30.............0.1
mAl dư = ( 0.1 - 1/15) * 27 = 0.9 (g)
mAl2(SO4)3 = 1/30 * 342 = 11.4 (g)
VH2 = 0.1*22.4 = 2.24 (l)
PTHH: \(2Al+3H_2SO_{4\left(loãng\right)}\rightarrow Al_2\left(SO_4\right)_3+3H_2\uparrow\)
Ta có: \(\left\{{}\begin{matrix}n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\\n_{H_2SO_4}=\dfrac{9,8}{98}=0,1\left(mol\right)\end{matrix}\right.\)
Xét tỉ lệ: \(\dfrac{0,1}{2}>\dfrac{0,1}{3}\) \(\Rightarrow\) Axit p/ứ hết, Nhôm còn dư
\(\Rightarrow\left\{{}\begin{matrix}n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{30}\left(mol\right)\\n_{H_2}=0,1\left(mol\right)\\n_{Al\left(dư\right)}=\dfrac{1}{30}\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{Al_2\left(SO_4\right)_3}=\dfrac{1}{30}\cdot342=11,4\left(g\right)\\V_{H_2}=0,1\cdot22,4=2,24\left(l\right)\\m_{Al\left(dư\right)}=27\cdot\dfrac{1}{30}=0,9\left(g\right)\end{matrix}\right.\)