Mg+2HCl\(\rightarrow\)MgCl2+H2

2Al+6HCl\(\rightarrow\)2AlCl3+3H2

Fe+2HCl\(\rightarrow\)FeCL2+H2

Gọi số mol H2 là a

Theo phương trình ta thấy nHCl=2nH2=2a

Theo bảo toàn khối lượng ta có

mKimloai+mHCl=m muối+mH2

\(\rightarrow\)24,6+36,5.2a=84,95+2a

\(\rightarrow\)a=0,85\(\rightarrow\)V=19,04l

Chọn C

Đáp án C.

→ n C l - =   2 n H 2   =   0 , 16   → m m u o i   = 4 , 34   +   0 , 16 . 35 , 5   = 10 , 02

Mg + 2HCl --> MgCl₂ + H₂

Fe + 2HCl --> FeCl₂ + H₂

2Al + 6HCl --> 2AlCl₃ + 3H₂

=> n_HCl = 2.n_H2

Theo ĐLBTKL: \(m_X+m_{HCl}=m_{muoi}+m_{H_2}\)

=> \(10,7+36,5.2.n_{H_2}=35,55+2.n_{H_2}\)

=> \(n_{H_2}=0,35\left(mol\right)\)

=> \(V_{H_2}=0,35.22,4=7,84\left(l\right)\)

Đáp án B.

Đáp án B

Đáp án B

\(n_{HCl}=0,8.0,5=0,4\left(mol\right);n_{H_2SO_4}=0,8.0,75=0,6\left(mol\right)\)

=> \(n_{Cl^-}=0,4\left(mol\right);n_{SO_4^{2-}}=0,6\left(mol\right)\)

\(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)

Bảo toàn nguyên tố H:

\(n_{HCl}.1+n_{H_2SO_4}.2=n_{H_2}.2+n_{H_2O}.2\)

\(\Leftrightarrow0,4.1+0,6.2=0,2.2+n_{H_2O}.2\)

=>\(n_{H_2O}=0,6\left(mol\right)\)

=> \(n_O=0,6\left(mol\right)\)

\(m_{muối}=m_{kimloai}+m_{Cl^-}+m_{SO_4^{2-}}\)

=>\(m_{kimloai}=88,7-35,5.0,4-0,6.96=16,9\left(g\right)\)

=> \(m=m_{kimloai}+m_O=16,9+0,6.16=26,5\left(g\right)\)

Bài 1:

\(n_{HCl}=2.0,16=0,32\left(mol\right);n_{H_2}=\dfrac{3,584}{22,4}=0,16\left(mol\right)\)

PTHH: Mg + 2HCl → MgCl₂ + H₂

PTHH: Fe + 2HCl → FeCl₂ + H₂

\(m_{H_2}=0,16.2=0,32\left(g\right)\)

\(m_{HCl}=0,32.36,5=11,68\left(g\right)\)

Theo ĐLBTKL ta có: \(m_{MgCl_2+FeCl_2}=1,4+11,68-0,32=12,76\left(g\right)\)

Bài 12:

Theo ĐLBTKL, ta có:

\(m_{hhkl}+m_{O_2}=m_{hh.oxit}\\ \Leftrightarrow11,9+m_{O_2}=18,3\\ \Leftrightarrow m_{O_2}=18,3-11,9=6,4\left(g\right)\\ n_{O_2}=\dfrac{6,4}{32}=0,2\left(mol\right)\\ V_{O_2\left(đktc\right)}=0,2.22,4=4,48\left(l\right)\)

Chọn đáp án A

Ta có