H₂O \(\left\{{}\begin{matrix}\%H=\dfrac{2}{18}.100\%=11,11\%\\\%O=100\%-11,11\%=88,89\%\end{matrix}\right.\)

SO₂ \(\left\{{}\begin{matrix}\%S=\dfrac{32}{64}.100\%=50\%\\\%O=100\%-50\%=50\%\end{matrix}\right.\)

CO₂ \(\left\{{}\begin{matrix}\%C=\dfrac{12}{44}.100\%=27,27\%\\\%O=100\%-27,27\%=72,73\%\end{matrix}\right.\)

\(n_{H_2O}=\dfrac{m}{M}=\dfrac{1,8}{18}=0,1\left(mol\right)\)

Trong 1 phân tử nước có 2 nguyên tử H và 1 nguyên tử O, tổng cộng là 3 nguyên tử

Số nguyên tử có trong 0,1 mol nước: \(3.0,1.6.10^{23}=1,8.10^{23}\) (nguyên tử)

a) \(n_{SO_3}=\dfrac{m}{M}=\dfrac{32}{80}=0,4\left(mol\right)\)

PTHH: `SO_3 + H_2O -> H_2SO_4`

b) Theo PTHH: `n_{H_2SO_4} = n_{SO_3} = 0,4 (mol)`

`=> m_{H_2SO_4} = 0,4.98 = 39,2 (g)`

a) \(M_{H_2}=2\left(g/mol\right);d_{A/H_2}=\dfrac{M_A}{M_{H_2}}=18,25\)

=> \(M_A=2.18,25=36,5\left(g/mol\right)\)

b) \(\left\{{}\begin{matrix}n_{Cl}=\dfrac{36,5.97,26\%}{35,5}=1\left(mol\right)\\n_H=\dfrac{36,5-35,5}{1}=1\left(mol\right)\end{matrix}\right.\)

=> A: HCl

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

PTHH: Zn + H₂SO₄ ---> ZnSO₄ + H₂

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

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

b) \(m_{\text{dd}H_2SO_4}=\dfrac{0,1.98}{19,6\%}=50\left(g\right)\)

=> \(m_{\text{dd}.sau.p\text{ư}}=50+6,5-0,1.2=56,3\left(g\right)\)

=> \(C\%_{ZnSO_4}=\dfrac{0,1.161}{56,3}.100\%=28,6\%\)

- \(n_{Fe}=\dfrac{m}{M}=\dfrac{5,6}{56}=0,1\left(mol\right)\)

- \(n_{H_2}=\dfrac{V_{\left(\text{đ}ktc\right)}}{22,4}=\dfrac{5,6}{22,4}=0,25\left(mol\right)\)

- \(n_{Cu}=\dfrac{3,0115.10^{23}}{6.10^{23}}=0,5\left(mol\right)\)

- K₂CO₃ \(\left\{{}\begin{matrix}\%K=\dfrac{78}{138}.100\%=56,52\%\\\%C=\dfrac{12}{138}.100\%=8,7\%\\\%O=100\%-56,52\%-8,7\%=34,78\%\end{matrix}\right.\)

Ta có: \(\left\{{}\begin{matrix}n_{NaOH}=0,5.0,5=0,25\left(mol\right)\\n_{KOH}=0,5.0,5=0,25\left(mol\right)\\n_{CO_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\end{matrix}\right.\)

Đặt CT chung của NaOH và KOH là AOH

=> \(n_{AOH}=n_{NaOH}+n_{KOH}=0,25+0,25=0,5\left(mol\right)\)

PTHH:           2AOH + CO₂ \(\rightarrow\) A₂CO₃ + H₂O
Ban đầu:         0,5        0,4

Pư:                 0,5----->0,25

Sau pư:           0          0,15       0,25

                    A₂CO₃ + CO₂ + H₂O \(\rightarrow\) 2AHCO₃ 

Ban đầu:       0,25       0,15

Pư:               0,15<----0,15

Sau pư:         0,1          0                       0,3

=> \(\dfrac{1}{2}\) ddY có: \(\left\{{}\begin{matrix}n_{A_2CO_3}=\dfrac{0,1}{2}=0,05\left(mol\right)\\n_{AHCO_3}=\dfrac{0,3}{2}=0,15\left(mol\right)\end{matrix}\right.\)

PTHH:          \(A_2CO_3+Ba\left(OH\right)_2\rightarrow BaCO_3\downarrow+2AOH\)

                      0,05--------------------->0,05

                      \(AHCO_3+Ba\left(OH\right)_{2\left(d\text{ư}\right)}\rightarrow BaCO_3\downarrow+AOH+H_2O\)

                       0,15-------------------------->0,15

                      \(A_2CO_3+BaCl_2\rightarrow BaCO_3\downarrow+2ACl\)

                       0,05------------------->0,05

=> \(\left\{{}\begin{matrix}a=\left(0,15+0,05\right).197=39,4\left(g\right)\\b=0,05.197=9,85\left(g\right)\end{matrix}\right.\)

=> a - b = 39,4 - 9,85 = 29,55 (g)

\(\left\{{}\begin{matrix}n_{H_2SO_4}=0,2.1=0,2\left(mol\right)\\n_{BaCl_2}=\dfrac{200.10,4\%}{208}=0,1\left(mol\right)\end{matrix}\right.\)

PTHH:        BaCl₂ + H₂SO₄ \(\rightarrow\) BaSO₄\(\downarrow\) + 2HCl

Ban đầu:     0,1          0,2

Pư:             0,1------->0,1

Sau pư:      0              0,1            0,1

=> \(m=m_{B\text{aS}O_4}=0,1.233=23,3\left(g\right)\)

a) \(n_{MgCO_3}=\dfrac{16,8}{84}=0,2\left(mol\right)\)

PTHH: MgCO₃ + 2HCl ---> MgCl₂ + CO₂ + H₂O

            0,2--------------------->0,2----->0,2

=> \(m=m_{MgCl_2}=0,2.95=19\left(g\right)\)

\(m_{\text{dd}.sau.p\text{ư}}=150+16,8-0,2.44=158\left(g\right)\)

=> \(C\%_{MgCl_2}=\dfrac{19}{158}.100\%=12,025\%\)

b) CO₂ + Ca(OH)₂ ---> CaCO₃ + H₂O

     0,2----->0,2------------>0,2

=> \(\left\{{}\begin{matrix}m_{kt}=m_{CaCO_3}=0,2.100=20\left(g\right)\\V_{\text{dd}Ca\left(OH\right)_2}=\dfrac{0,2}{3}=\dfrac{1}{15}\left(l\right)\end{matrix}\right.\)