\(n_{Cl_2}=\dfrac{11.2}{22.4}=0.5\left(mol\right)\)

\(2KMnO_4+16HCl_{\left(đ\right)}\rightarrow2KCl+2MnCl_2+5Cl_2+8H_2O\)

\(0.2...................1.6...........................................0.5\)

\(m_{KMnO_4}=0.2\cdot158=31.6\left(g\right)\)

\(V_{dd_{HCl}}=\dfrac{1.6}{1}=1.6\left(l\right)=1600\left(ml\right)\)

\(n_{Cl_2}=\dfrac{11,2}{22,4}=0,5(mol)\\ PTHH:2KMnO_4+16HCl\to 2KCl+2MnCl_2+5Cl_2+8H_2O\\ \Rightarrow n_{KMnO_4}=\dfrac{2}{5}n_{Cl_2}=0,2(mol);n_{HCl}=\dfrac{16}{5}n_{Cl_2}=1,6(mol)\\ \Rightarrow m_{KMnO_4}=0,2.158=31,6(g);V_{dd_{HCl}}=\dfrac{1,6}{1}=1,6(l)=1600(ml)\)

2Al+6HCl->2AlCl3+3H2

0,5----1,5-------------------------0,75

n H2=0,075 mol

cần 10 quả bóng =>0,075.10=0,75 mol

=>mAl=0,5.27=13,5g

m HCl=1,5.36,5=54,75g

=>m dd=75g

\(n_{H_2}=\dfrac{1,68}{22,4}=0,075\left(mol\right)\\ pthh:2Al+6HCl\rightarrow2AlCl_3+3H_2\) 
           0,1125   0,15                     0,075 
\(m_{Al}=0,1125.27=3,0375\left(g\right)\\ m_{HCl}=\dfrac{\left(0,15.36,5\right).100}{7,3}=75\left(g\right)\) 

\(n_{FeCl_3}=\dfrac{16.25}{162.5}=0.1\left(mol\right)\)

\(Fe+\dfrac{3}{2}Cl_2\underrightarrow{t^0}FeCl_3\)

\(......0.15......0.1\)

\(2KMnO_4+16HCl\rightarrow2KCl+2MnCl_2+5Cl_2+8H_2O\)

\(0.06...............0.48........................................0.15\)

\(m_{KMnO_4}=0.06\cdot158=9.48\left(g\right)\)

\(V_{dd_{HCl}}=\dfrac{0.48}{1}=0.48\left(l\right)=480\left(ml\right)\)

\(2Fe+ 3Cl_2 \xrightarrow{t^o} 2FeCl_3\\ n_{Cl_2} = \dfrac{3}{2}n_{FeCl_3} = \dfrac{3}{2}.\dfrac{16,25}{162,5} = 0,15(mol)\\ 2KMnO_4 + 16HCl \to 2KCl + 2MnCl_2 + 5Cl_2 + 8H_2O\\ n_{KMnO_4} = \dfrac{2}{5}n_{Cl_2} = 0,06(mol)\\ \Rightarrow m_{KMnO_4} = 0,06.158 = 9,48(gam)\\ n_{HCl} = \dfrac{16}{4}n_{Cl_2} = 0,48(mol)\\ \Rightarrow V_{dd\ HCl} = \dfrac{0,48}{1} = 0,48(lít) = 480(ml)\)

Câu 2 : 

$n_{HCl} = 0,2.1 + 0,3.1,5 = 0,65(mol)$
$V_{dd} = 0,2 + 0,3 = 0,5(mol)$
$C_{M_{HCl}} = \dfrac{0,65}{0,5} =1,3M$

Câu 3 : 

Gọi $m_{H_2O\ cần\ thêm} =a (gam)$

Sau khi thêm : 

$m_{NaOH} = 100.35\% = 35(gam)$
$m_{dd} = 100 + a(gam)$

Suy ra:  $\dfrac{35}{100 + a}.100\% = 20\%$

Suy ra: a = 75(gam)

Câu 4 : 

Gọi $V_{dd\ HCl\ 2M} =a (lít) ; V_{dd\ HCl\ 3M} = b(lít)$

Ta có : 

$a + b = 4$
$2a + 3b = 4.2,75$

Suy ra a = 1(lít) ; b = 3(lít)

a) \(n_{Fe_2O_3}=\dfrac{32}{160}=0,2\left(mol\right)\)

PTHH: Fe₂O₃ + 3H₂ --t^o--> 2Fe + 3H₂O

            0,2----->0,6

=> V_H2 = 0,6.22,4 = 13,44 (l)

b) PTHH: 2Al + 6HCl ---> 2AlCl₃ + 3H₂

                0,4<-1,2<------------------0,6

=> \(m_{ddHCl}=\dfrac{1,2.36,5}{20\%}=219\left(g\right)\)

c) PTHH: 4Al + 3O₂ --t^o--> 2Al₂O₃ 

              0,4<---0,3

=> V_kk = 0,3.22,4.5 = 33,6 (l)

b) dd gì 20% ?

\(m_{NaOH\left(35\%\right)}=100.35\%=35\left(g\right)\)

\(m_{ddNaOH\left(20\%\right)}=\dfrac{35}{20}.100=175\left(g\right)\)

⇒ m_{nước thêm vào} = 175-100 = 75(g)

_{Vnước thêm vào} = 75.1 = 75 (ml)

Câu 4:

\(n_{HCl}=4.2,75=11\left(mol\right)\)

Ta có: \(V_{ddHCl\left(2M\right)}=\dfrac{n_{HCl\left(1\right)}}{2}\left(l\right);V_{ddHCl\left(3M\right)}=\dfrac{n_{HCl\left(2\right)}}{3}\left(l\right)\)

  \(\Rightarrow V_{ddHCl\left(2M\right)}+V_{ddHCl\left(3M\right)}=\dfrac{n_{HCl\left(1\right)}}{2}+\dfrac{n_{HCl\left(2\right)}}{3}\)

  \(\Leftrightarrow4=\dfrac{3n_{HCl\left(1\right)}+2n_{HCl\left(2\right)}}{6}\Leftrightarrow3n_{HCl\left(1\right)}+2n_{HCl\left(2\right)}=24\)

Ta có: \(\left\{{}\begin{matrix}n_{HCl\left(1\right)}+n_{HCl\left(2\right)}=11\\3n_{HCl\left(1\right)}+2n_{HCl\left(2\right)}=24\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}n_{HCl\left(1\right)}=2\\n_{HCl\left(2\right)}=9\end{matrix}\right.\)

  \(\Rightarrow V_{ddHCl\left(2M\right)}=\dfrac{2}{2}=1\left(l\right);V_{ddHCl\left(3M\right)}=\dfrac{9}{3}=3\left(l\right)\)

Câu 3:

\(m_{NaOH}=35.100\%=35\left(g\right)\\ m_{H_2O\left(thêm\right)}=a\left(g\right)\\ \Rightarrow\dfrac{35}{100+a}.100\%=20\%\\ \Leftrightarrow a=75\left(g\right)\\ \Rightarrow V_{H_2O\left(thêm\right)}=\dfrac{75}{1}=75\left(ml\right)\)

Câu 4:

\(Đặt:V_{ddHCl\left(pha.thêm2M\right)}=a\left(l\right)\\ V_{ddHCl\left(pha.thêm3M\right)}=b\left(l\right)\\ \Rightarrow\dfrac{2a+3b}{a+b}=2,75\left(1\right)\\ Mà:a+b=4\left(2\right)\\ Từ\left(1\right),\left(2\right)\Rightarrow\left\{{}\begin{matrix}a=1\left(l\right)\\b=3\left(l\right)\end{matrix}\right.\)

Vậy cần pha 1 lít dung dịch HCl 2M vào 3 lít dung dịch HCl 3M để thu được 4 lít dung dịch HCl 2,75M 

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