\(n_{Al}=\dfrac{8.1}{27}=0.3\left(mol\right)\)

\(n_{H_2SO_4}=\dfrac{29.4}{98}=0.3\left(mol\right)\)

\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)

\(2.........3\)

\(0.3..........0.3\)

\(LTL:\dfrac{0.3}{2}>\dfrac{0.3}{3}\Rightarrow Aldư\)

\(V_{H_2}=0.3\cdot22.4=6.72\left(l\right)\)

\(m_{Al\left(dư\right)}=\left(0.3-0.2\right)\cdot27=2.7\left(g\right)\)

PT: \(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)

a, Ta có: \(n_{Al}=\dfrac{5,4}{27}=0,2\left(mol\right)\)

\(n_{H_2SO_4}=\dfrac{30}{98}=\dfrac{15}{49}\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,2}{2}< \dfrac{\dfrac{15}{49}}{3}\) , ta được H₂SO₄ dư.

b, Theo PT: \(n_{H_2}=\dfrac{3}{2}n_{Al}=0,3\left(mol\right)\)

\(\Rightarrow V_{H_2}=0,3.22,4=6,72\left(l\right)\)

c, Sau phản ứng, trong cốc có H₂SO₄ dư và Al₂(SO₄)₃.

Theo PT: \(\left\{{}\begin{matrix}n_{H_2SO_4\left(pư\right)}=\dfrac{3}{2}n_{Al}=0,3\left(mol\right)\\n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{2}n_{Al}=0,1\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow n_{H_2SO_4\left(dư\right)}=\dfrac{15}{49}-0,3\approx0,006\left(mol\right)\)

\(\Rightarrow\left\{{}\begin{matrix}m_{H_2SO_4\left(dư\right)}=0,006.98=0,588\left(g\right)\\m_{Al_2\left(SO_4\right)_3}=0,1.342=34,2\left(g\right)\end{matrix}\right.\)

Bạn tham khảo nhé!

 PTHH: \(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\uparrow\)

Làm gộp các phần còn lại

Ta có: \(n_{Al}=\dfrac{5,4}{27}=0,2\left(mol\right)\) \(\Rightarrow\left\{{}\begin{matrix}n_{Al_2\left(SO_4\right)_3}=0,1mol\\n_{H_2SO_4}=n_{H_2}=0,3mol\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}V_{H_2}=0,3\cdot22,4=6,72\left(l\right)\\m_{Al_2\left(SO_4\right)_3}=0,1\cdot342=34,2\left(g\right)\\m_{H_2SO_4}=0,3\cdot98=29,4\left(g\right)\end{matrix}\right.\) 

$a\big)2Al+3H_2SO_4\to Al_2(SO_4)_3+3H_2$

$b\big)$

$n_{Al}=\dfrac{4,05}{27}=0,15(mol)$

$n_{H_2SO_4}=\dfrac{29,4}{98}=0,3(mol)$

Vì $\dfrac{n_{Al}}{2}<\frac{n_{H_2SO_4}}{3}\to H_2SO_4$ dư

$c\big)$

Theo PT: $n_{H_2}=\dfrac{3}{2}n_{Al}=0,225(mol)$

$\to V_{H_2}=0,225.22,4=5,04(l)$

a)

$n_{Al} = \dfrac{8,1}{27} = 0,3(mol)$

$2Al + 6HCl \to 2AlCl_3 + 3H_2$
Theo PTHH : 

$n_{H_2} = \dfrac{3}{2}n_{Al} = 0,45(mol)$
$V_{H_2} = 0,45.22,4 = 10,08(lít)$

b) $n_{HCl} = 3n_{Al} = 0,9(mol)$
$\Rightarrow m_{dd\ HCl} = \dfrac{0,9.36,5}{3,65\%} = 900(gam)$

c)

$m_{dd\ sau\ pư}= 8,1 + 900 - 0,45.2 = 907,2(gam)$

$n_{Al_2(SO_4)_3} = \dfrac{1}{2}n_{Al} = 0,15(mol)$
$C\%_{Al_2(SO_4)_3} = \dfrac{0,15.342}{907,2}.100\% = 5,65\%$

a) 4Al : 4 nguyên tử Nhôm

b) $2Al(OH)_3$ : 2 phân tử Nhôm hidroxit

c) $3O_2$ : 3 phân tử oxi

d) $12C_6H_{12}O_6$ : 12 phân tử glucozo

Diễn đạt các cách viết sau:

a)   4Al =>4 nguyên tử Al

b)   2 Al(OH)3=>2 nguyên tử nhôm hidroxit

c)   3O2 =>3 nt khí oxi

d)   12C6H12O6 =>12 nt đường sacarozo

2Al+3H₂SO₄->Al₂(SO₄)₃+3H₂

0,2-----0,3-------0,1------------0,3

n _Al=\(\dfrac{5,4}{27}\)=0,2 mol

n _H2SO4= \(\dfrac{30}{98}\)=0,306 mol

=>H2SO4 còn dư

=>V_H2=0,3.22,4=6,72l

=>m _Al2(SO4)3=0,1.342=34,2g

=>m _{H2SO4 dư}=0,006.98=0,588g

\(n_{Al}=\dfrac{m_{Al}}{M_{Al}}=\dfrac{5,4}{27}=0,2mol\)

\(n_{H_2SO_4}=\dfrac{m_{H_2SO_4}}{M_{H_2SO_4}}=\dfrac{30}{98}=\dfrac{15}{49}mol\)

\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)

 2            3                  1                 3      ( mol )

0,2      15/49          ( mol )

Ta có: \(\dfrac{0,2}{2}< \dfrac{15}{49}:3\)

=> Chất còn dư là \(H_2SO_4\)

\(V_{H_2}=n_{H_2}.22,4=\left(\dfrac{0,2.3}{2}\right).22,4=6,72l\)

\(m_{Al_2\left(SO_4\right)_3}=n_{Al_2\left(SO_4\right)_3}.M_{Al_2\left(SO_4\right)_3}=\left(\dfrac{0,2.1}{2}\right).342=34,2g\)

\(m_{H_2SO_4\left(du\right)}=n_{H_2SO_4\left(du\right)}.M_{H_2SO_4}=\left(\dfrac{15}{49}-\dfrac{0,2.3}{2}\right).98=0,6g\)

a)

$n_{Al} = 0,3(mol)$

$2Al + 3H_2SO_4 \to Al_2(SO_4)_3 + 3H_2$

Theo PTHH : 

$n_{H_2SO_4} = \dfrac{3}{2}n_{Al} = 0,45(mol)$
$m_{dd\ H_2SO_4} = \dfrac{0,45.98}{12,25\%} = 360(gam)$

b)

$n_{H_2} = n_{H_2SO_4} = 0,45(mol)$
$V_{H_2} = 0,45.22,4 = 10,08(lít)$

c)

$n_{Al_2(SO_4)_3} = 0,15(mol)$
$m_{dd\ sau\ pư} = 8,1 + 360 - 0,45.2 = 367,2(gam)$
$C\%_{Al_2(SO_4)_3} = \dfrac{0,15.342}{367,2}.100\% = 14\%$