a) $2Al + 3H_2SO_4 \to Al_2(SO_4)_3 + 3H_2$
b) $n_{Al} = 0,45(mol) ; n_{H_2SO_4} =\dfrac{219}{980} (mol)$
Ta thấy :
$n_{Al} : 2 > n_{H_2SO_4} : 3$ nên Al dư
Theo PTHH :
$n_{Al\ pư} = \dfrac{2}{3}n_{H_2SO_4} = \dfrac{73}{490} (mol)$
$m_{Al\ dư} = 12,15 - \dfrac{73}{490}.27 = 8,127(gam)$
c) $n_{Al_2(SO_4)_3} = \dfrac{1}{3}n_{H_2SO_4} = \dfrac{73}{930}(mol)$
$m_{muối} = \dfrac{73}{930}.342 = 25,48(gam)$
d) $V_{H_2} = \dfrac{219}{980}.22,4 = 5(lít)$
Hình như đề sai
a,\(n_{Al}=\dfrac{12,15}{27}=0,45\left(mol\right)\)
\(m_{H_2SO_4}=109,5.20\%=21,9\left(g\right)\Rightarrow n_{H_2SO_4}=\dfrac{21,9}{98}=0,2235\left(mol\right)\)
\(a.2Al+6HCl\rightarrow2AlCl_3+3H_2\\ n_{Al}=\dfrac{12,15}{27}=0,45\left(mol\right)\\ n_{HCl}=\dfrac{20\%.109,5}{36,5}=0,6\left(mol\right)\\ b.Vì:\dfrac{0,45}{2}>\dfrac{0,6}{6}\\ \Rightarrow Aldư\\ n_{Al\left(dư\right)}=0,45-\dfrac{2}{6}.0,6=0,25\left(mol\right)\\ m_{Al\left(dư\right)}=0,25.27=6,75\left(g\right)\\ c.n_{AlCl_3}=\dfrac{2}{6}.0,6=0,2\left(mol\right)\\ m_{AlCl_3}=0,2.133,5=26,7\left(g\right)\\ d.n_{H_2}=\dfrac{3}{6}.0,6=0,3\left(mol\right)\\ V_{H_2\left(đktc\right)}=0,3.22,4=6,72\left(l\right)\)
