Khối lượng  H 2 SO 4  cần dùng :

m H 2 SO 4  = 0,01.98 = 0,98g

⇒  m dd   H 2 SO 4  = 0,98 : 19,8% = 4,95g

n Fe  = 0,56/56 = 0,01 mol

Fe +  H 2 SO 4  →  FeSO 4  +  H 2

n FeSO 4  =  n Fe  = 0,01

a) PTHH: \(Fe+H_2SO_4\rightarrow FeSO_4+H_2\uparrow\)

b) Ta có: \(n_{Fe}=\dfrac{0,56}{56}=0,01\left(mol\right)=n_{FeSO_4}=n_{H_2}\)

\(\Rightarrow\left\{{}\begin{matrix}m_{FeSO_4}=0,01\cdot152=1,52\left(g\right)\\V_{H_2}=0,01\cdot22,4=0,224\left(l\right)\end{matrix}\right.\)

c) Theo PTHH: \(n_{Fe}=n_{H_2SO_4}=0,01\left(mol\right)\)

\(\Rightarrow m_{ddH_2SO_4}=\dfrac{0,01\cdot98}{19,6\%}=5\left(g\right)\)

a) \(Pt:Fe+H_2SO_4\rightarrow FeSO_4+H_2\)

b) \(n_{Fe}=\dfrac{0,56}{56}=0,01mol\)

Theo pt: \(n_{FeSO_4}=n_{Fe}=0,01mol\)

\(\Rightarrow m_{FeSO_4}=0,01.152=1,52g\)

Theo pt: \(n_{H_2}=n_{Fe}=0,01mol\)

\(\Rightarrow V_{H_2}=0,01.22,4=0,224lít\)

c) \(Theopt:nH_2SO_4=n_{Fe}=0,01mol\)

\(\Rightarrow m_{H_2SO_4}=0,01.98=0,98g\)

\(\Rightarrow m_{ddH_2SO_4}=\dfrac{0,98.100}{19,6}=5g\)

4.1)

a) \(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)

PTHH: Zn + H₂SO_{4 (loãng)} ---> ZnSO₄ + H₂ 

           0,1---->0,1---------------------------->0,1

b) \(V_{H_2}=0,1.22,4=2,24\left(l\right)\)

c) \(m_{ddH_2SO_4}=\dfrac{0,1.98}{19,6\%}=50\left(g\right)\)

4.2)

Gọi kim loại hóa trị II là R; \(n_{AgCl}=\dfrac{2,87}{143,5}=0,02\left(mol\right)\)
PTHH: \(RCl_2+2AgNO_3\rightarrow R\left(NO_3\right)_2+2AgCl\downarrow\)

           0,01<-----------------------------------0,02

=> \(M_{RCl_2}=\dfrac{0,95}{0,01}=95\left(g/mol\right)\)

=> \(M_R=95-71=24\left(g/mol\right)\)

Mà R có hóa trị II => R là Magie (Mg)

Câu 5:

a) Gọi \(\left\{{}\begin{matrix}n_{CuO}=a\left(mol\right)\\n_{Al_2O_3}=b\left(mol\right)\end{matrix}\right.\left(ĐK:a,b>0\right)\)

=> 80a + 102b = 14,2 (1)

n_HCl = 0,2.3,5 = 0,7 (mol)

PTHH:
CuO + 2HCl ---> CuCl₂ + H₂O

a------>2a

Al₂O₃ + 6HCl ---> 2AlCl₃ + 3H₂O

b------->6b

b) 2a + 2b = 0,7 (2)
Từ (1), (2) => a = 0,05; b = 0,1

=> \(\left\{{}\begin{matrix}\%m_{CuO}=\dfrac{0,05.80}{14,2}.100\%=28,17\%\\\%m_{Al_2O_3}=100\%-28,17\%=71,83\%\end{matrix}\right.\)

a, \(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)

Ta có: \(n_{Fe}=\dfrac{0,56}{56}=0,01\left(mol\right)\)

Theo PT: \(n_{H_2SO_4}=n_{FeSO_4}=n_{H_2}=n_{Fe}=0,01\left(mol\right)\)

b, \(m_{FeSO_4}=0,01.152=1,52\left(g\right)\)

\(V_{H_2}=0,01.22,4=0,224\left(l\right)\)

c, \(m_{ddH_2SO_4}=\dfrac{0,01.98}{19,6\%}=5\left(g\right)\)

a)

$Fe + H_2SO_4 \to FeSO_4 + H_2$

Theo PTHH : 

$n_{H_2} = n_{H_2SO_4} = n_{Fe} = \dfrac{0,56}{56} = 0,01(mol)$
$V_{H_2} = 0,01.22,4 = 0,224(lít)$

b) $C_{M_{H_2SO_4}} = \dfrac{0,01}{0,2} = 0,05M$

hkhkhkhkhkhkhkhkhkhkhkhkhkhkhkhkhkhkhkhkhkhkhkhk