nKClO3 = 49 : 122,5 =0,4(mol) 
a) pthh : 2KClO3 -t--> 2KCl + 3O2
               0,4------------>0,4----->0,6(mol)
 mKCl = 0,4.74,5=29,8 (g) 
VO2= 0,6.22,4= 13,44 (l)
câu 2 
a nZn = 6,5:65=0,1(mol) 
pthh : Zn +2HCl ---> ZnCl2 + H2
           0,1->0,2----------------->0,1(mol) 
=> VH2 = 0,1.22,4 =2,24(l)
=> mHCl = 0,2 . 36,5=7,3 (g)

a, \(n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\)

 \(m_{HCl}=109,5.10\%=10,95\left(g\right)\Rightarrow n_{HCl}=\dfrac{10,95}{36,5}=0,3\left(mol\right)\)

PTHH: 2Al + 6HCl → 2AlCl₃ + 3H₂

Mol:      0,1      0,3         0,1       0,15

Ta có: \(\dfrac{0,1}{2}=\dfrac{0,3}{6}\) ⇒ Al hết, HCl hết

\(V_{H_2}=0,15.22,4=3,36\left(l\right)\)

b, \(m_{AlCl_3}=0,1.133,5=13,35\left(g\right)\)

c, m_{dd sau pứ} = 2,7 + 109,5 - 0,15.2 = 111,9 (g)

\(C\%_{ddAlCl_3}=\dfrac{13,35.100\%}{111,9}=11,93\%\)

PTHH: \(2Al+6HCl\rightarrow2AlCl_3+3H_2\uparrow\)

Ta có: \(\left\{{}\begin{matrix}n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\\n_{HCl}=\dfrac{109,5\cdot10\%}{36,5}=0,3\left(mol\right)\end{matrix}\right.\)

Xét tỉ lệ: \(\dfrac{0,1}{2}=\dfrac{0,3}{6}\) \(\Rightarrow\) Al và HCl đều p/ứ hết

\(\Rightarrow\left\{{}\begin{matrix}n_{AlCl_3}=0,1\left(mol\right)\\n_{H_2}=0,15\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{AlCl_3}=0,1\cdot133,5=13,35\left(g\right)\\V_{H_2}=0,15\cdot22,4=3,36\left(l\right)\\m_{H_2}=0,15\cdot2=0,3\left(g\right)\end{matrix}\right.\)

Mặt khác: \(m_{dd}=m_{Al}+m_{ddHCl}-m_{H_2}=111,9\left(g\right)\)

\(\Rightarrow C\%_{AlCl_3}=\dfrac{13,35}{111,9}\cdot100\%\approx11,93\%\)

a) 

\(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)

PTHH: Zn + 2HCl --> ZnCl₂ + H₂

            0,2-->0,4----->0,2--->0,2

=> V_H2 = 0,2.22,4 = 4,48 (l)

b) m_HCl = 0,4.36,5 = 14,6 (g)

=> \(m_{dd.HCl}=\dfrac{14,6.100}{7,3}=200\left(g\right)\)

c)

m_{dd sau pư} = 13 + 200 - 0,2.2 = 212,6 (g)

m_ZnCl2 = 0,2.136 = 27,2 (g)

=> \(C\%=\dfrac{27,2}{212,6}.100\%=12,8\%\)

a, \(Zn+2HCl\rightarrow ZnCl_2+H_2\)

b, \(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)

Theo PT: \(n_{H_2}=n_{Zn}=0,2\left(mol\right)\Rightarrow V_{H_2}=0,2.22,4=4,48\left(l\right)\)

c, \(n_{ZnCl_2}=n_{Zn}=0,2\left(mol\right)\Rightarrow m_{ZnCl_2}=0,2.136=27,2\left(g\right)\)

d, \(n_{HCl}=2n_{Zn}=0,4\left(mol\right)\Rightarrow m_{HCl}=0,4.36,5=14,6\left(g\right)\)

\(\Rightarrow m_{ddHCl}=\dfrac{14,6}{7,3\%}=200\left(g\right)\)

⇒ m _{dd sau pư} = 13 + 200 - 0,2.2 = 212,6 (g)

\(\Rightarrow C\%_{ZnCl_2}=\dfrac{27,2}{212,6}.100\%\approx12,79\%\)

a, PT: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)

Ta có: \(n_{Zn}=\dfrac{4,8}{65}=\dfrac{24}{325}\left(mol\right)\)

Đến đây thì ra số mol hơi xấu, bạn xem lại đề nhé.

PTHH: \(Zn+2HCl\rightarrow ZnCl_2+H_2\uparrow\)

Ta có: \(n_{Zn}=\dfrac{32,5}{65}=0,5\left(mol\right)\)

\(\Rightarrow\left\{{}\begin{matrix}n_{HCl}=1\left(mol\right)\\n_{H_2}=0,5\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{ddHCl}=\dfrac{1\cdot36,5}{20\%}=182,5\left(g\right)\\V_{H_2}=0,5\cdot22,4=11,2\left(l\right)\end{matrix}\right.\)

a) n Fe = 28/56 = 0,5(mol)

$Fe + 2HCl \to FeCl_2 + H_2$

Theo PTHH :

n HCl = 2n Fe = 1(mol)

=> m dd HCl = 1.36,5/10% = 365(gam)

b)

n FeCl2 = n H2 = n Fe = 0,5(mol)

Suy ra : 

V H2 = 0,5.22,4 = 11,2(lít)

m FeCl2 = 0,5.127 = 63,5(gam)

c)

Sau phản ứng: 

mdd = m Fe + mdd HCl - m H2 = 28 + 365 - 0,5.2 = 392(gam)

=> C% FeCl2 = 63,5/392   .100% = 16,2%