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a) Gọi hóa trị của kim loại A là n(n>0,n∈Z)
\(n_A=\dfrac{5,4}{A}mol\\ n_{A_2\left(SO_4\right)_n}=\dfrac{342.10\%}{100\%.\left(2A+96n\right)}mol\\ 2A+nH_2SO_4\rightarrow A_2\left(SO_4\right)_n+nH_2\\ \Rightarrow n_A:2=n_{A_2\left(SO_4\right)_n}\\ \Leftrightarrow\dfrac{5,4}{A}:2=\dfrac{342.10\%}{100\%\left(2A+96n\right)}\\ \Leftrightarrow A=9n\)
Với n = 3 thì A = 27(TM)
Vậy kim loại A là Nhôm
\(n_{XCl_3}=\dfrac{a}{M_X+106,5}\left(mol\right)\)
PTHH: 2X + 6HCl --> 2XCl3 + 3H2
=> \(n_X=\dfrac{a}{M_X+106,5}\left(mol\right)\)
\(n_{X_2\left(SO_4\right)_3}=\dfrac{b}{2.M_X+288}\left(mol\right)\)
PTHH: 2X + 3H2SO4 --> X2(SO4)3 + 3H2
=> \(n_X=\dfrac{b}{M_X+144}\left(mol\right)\)
\(n_{H_2SO_4}=0,1.3=0,3\left(mol\right)\)
PT: \(Zn+H_2SO_4\rightarrow ZnSO_4+H_2\)
Theo PT: \(n_{Zn}=n_{H_2SO_4}=0,3\left(mol\right)\)
PT: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
Theo PT: \(n_{ZnCl_2}=n_{Zn}=0,3\left(mol\right)\Rightarrow m_{ZnCl_2}=0,3.136=40,8\left(g\right)\)
\(a.PTHH:Zn+2HCl\xrightarrow[]{}ZnCl_2+H_2\\ b.n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\\ PTHH:Zn+2HCl\xrightarrow[]{}ZnCl_2+H_2\\ n_{H_2}=0,2.2=0,4\left(mol\right)\\ V_{H_2}=0,4.22,4=8,96\left(l\right)\\ c.n_{HCl}=n_{Zn}=0,2mol\\ C_{MHCl}=\dfrac{0,4}{0,1}=4\left(M\right)\)
\(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)
PTHH :
\(Zn+2HCl\rightarrow ZnCl_2+H_2\uparrow\)
0,2 0,4 0,2 0,2
\(b,V_{H_2}=0,2.22,4=4,48\left(l\right)\)
\(c,C_M=\dfrac{n}{V}=\dfrac{0,4}{0,1}=4M\)
\(n_{A_2O}=\dfrac{9,4}{2M_A+16}\left(mol\right)\)
PTHH: A2O + 2HCl --> 2ACl + H2O
\(\dfrac{9,4}{2M_A+16}\)-->\(\dfrac{9,4}{M_A+8}\)
=> \(\dfrac{9,4}{M_A+8}\left(M_A+35,5\right)=14,9\Rightarrow M_A=39\left(g/mol\right)\)
=> A là K
CTHH: K2O
a)
\(PTHH:2Al+6HCl->2AlCl_3+3H_2\)
1,3<---4<-------1,3<---------2
b)
\(n_{H_2\left(dktc\right)}=\dfrac{V}{22,4}=\dfrac{44,8}{22,4}=2\left(mol\right)\)
\(m_{AlCl_3}=n\cdot M=1,3\cdot\left(27+35,5\cdot3\right)=173,55\left(g\right)\)
\(m_{Al}=n\cdot M=1,3\cdot27=35,1\left(g\right)\)
\(m_{ACl_3}=\dfrac{325.10}{100}=32,5g\\ n_{A_2O_3}=\dfrac{16}{2A+48}mol\\ n_{ACl_3}=\dfrac{32,5}{A+106,5}mol\\ A_2O_3+6HCl\rightarrow2ACl_3+3H_2O\\ \Rightarrow n_A=n_{ACl_3}:2\\ \Leftrightarrow\dfrac{16}{2A+48}=\dfrac{32,5}{A+106,5}:2\\ \Leftrightarrow A=56\)
Vậy A là Fe