Bài 6 : 

\(a) Mg + 2CH_3COOH \to (CH_3COO)_2Mg + H_2\\ n_{H_2} = n_{(CH_3COO)_2Mg} = n_{Mg} = \dfrac{9,6}{24} = 0,4(mol)\\ m_{dd\ sau\ pư} = 9,6 + 200 - 0,4.2 = 208,8(gam)\\ C\%_{(CH_3COO)_2Mg} = \dfrac{0,4.142}{208,8}.100\% = 27,2\%\\ b) V_{H_2} = 0,4.22,4 = 8,96(lít)\)

Bài 7 : 

\(a) n_{C_2H_5OH} = \dfrac{4,6}{46} = 0,1(mol)\\ C_2H_5OH + 3O_2 \xrightarrow{t^o} 2CO_2 + 3H_2O\\ n_{CO_2} = 2n_{C_2H_5OH} = 0,2(mol)\\ V_{CO_2} = 0,2.22,4 = 4,48(lít)\\ b) n_{O_2} = 3n_{C_2H_5OH} = 0,3(mol)\\ V_{kk} = \dfrac{0,3.22,4}{20\%} = 33,6(lít)\)

Bài 8 :

\(n_{CaCO_3} = \dfrac{12}{100} = 0,12(mol)\\ CaCO_3 + 2CH_3COOH \to (CH_3COO)_2Ca + CO_2 + H_2\\ n_{CH_3COOH} = 2n_{CaCO_3} = 0,24(mol)\\ C\%_{CH_3COOH} = \dfrac{0,24.60}{200}.100\% = 7,2\%\\ b) n_{CO_2} = n_{CaCO_3} = 0,12(mol)\\ V_{CO_2} = 0,12.22,4 = 2,688(lít)\)

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)

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

\(n_{H_2}=\dfrac{3,36}{22,4}=0,15(mol)\\ PTHH:Fe+H_2SO_4\to FeSO_4+H_2\\ \Rightarrow n_{H_2SO_4}=n_{H_2}=0,15(mol)\\ \Rightarrow C_{M_{H_2SO_4}}=\dfrac{0,15}{0,05}=3M\\ PTHH:2H_2+O_2\xrightarrow{t^o}2H_2O\\ \Rightarrow n_{O_2}=\dfrac{1}{2}n_{H_2}=0,075(mol)\\ \Rightarrow V_{O_2}=0,075.22,4=1,68(l)\)

a) \(n_{Al}=\dfrac{10,8}{27}=0,4\left(mol\right)\)

PTHH: 2Al + 3H₂SO₄ --> Al₂(SO₄)₃ + 3H₂

           0,4-->0,6---------->0,2------->0,6

=> \(C_{M\left(dd.H_2SO_4\right)}=\dfrac{0,6}{0,15}=4M\)

b) V_H2 = 0,6.22,4 = 13,44 (l)

c) \(C_{M\left(Al_2\left(SO_4\right)_3\right)}=\dfrac{0,2}{0,15}=\dfrac{4}{3}M\)

\(n_{Al}=\dfrac{10,8}{27}=0,4\left(mol\right)\\ pthh:2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\) 
           0,4     0,6                   0,2             0,6 
\(C_M_{H_2SO_4}=\dfrac{0,6}{0,15}=4M\\ V_{H_2}=0,622,4=13,44L\) 
\(C_M=\dfrac{0,2}{0,15}=1,3M\)

\(n_K=\dfrac{39}{39}=1\left(mol\right)\\ 2K+2H_2O\rightarrow2KOH+H_2\\ n_{H_2}=\dfrac{1}{2}=0,5\left(mol\right)\\ a,V_{H_2\left(đktc\right)}=0,5.22,4=11,2\left(l\right)\\ b,n_{KOH}=n_K=1\left(mol\right)\\ C_{MddKOH}=\dfrac{1}{0,2}=5\left(M\right)\\ c,2H_2+O_2\rightarrow\left(t^o\right)2H_2O\\ n_{O_2}=\dfrac{0,5}{2}=0,25\left(mol\right)\\ V_{O_2\left(đktc\right)}=0,25.22,4=5,6\left(l\right)\)

Ta có: \(n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)

a. PTHH: \(Zn+H_2SO_4--->ZnSO_4+H_2\uparrow\left(1\right)\)

b. Theo PT₍₁₎: \(n_{Zn}=n_{H_2}=0,3\left(mol\right)\)

\(\Rightarrow m_{Zn}=65.0,3=19,5\left(g\right)\)

c. Theo PT₍₁₎: \(n_{H_2SO_4}=n_{Zn}=0,3\left(mol\right)\)

Đổi 300ml = 0,3 lít

\(\Rightarrow C_{M_{H_2SO_4}}=\dfrac{0,3}{0,3}=1M\)

d. PTHH: \(2NaOH+H_2SO_4--->Na_2SO_4+2H_2O\left(2\right)\)

Theo PT₍₂₎: \(n_{NaOH}=2.n_{H_2SO_4}=2.0,3=0,6\left(mol\right)\)

\(\Rightarrow m_{NaOH}=0,6.40=24\left(g\right)\)

\(\Rightarrow m_{dd_{NaOH}}=\dfrac{24.100\%}{20\%}=120\left(g\right)\)

a)

$Fe + H_2SO_4 \to FeSO_4 + H_2$
$n_{H_2SO_4} = n_{H_2} = n_{Fe} = \dfrac{16,8}{56} = 0,3(mol)$

$V = 0,3.22,4 = 6,72(lít)$
$C_{M_{H_2SO_4}} = \dfrac{0,3}{0,25} = 1,2M$

b)

$n_{CuO} = \dfrac{16}{80} = 0,2(mol)$
$CuO + H_2 \xrightarrow{t^o} Cu + H_2O$
$n_{CuO} < n_{H_2}$ nên $H_2$ dư

$n_{Cu} = n_{CuO} = 0,2(mol)$
$m_{Cu} = 0,2.64 = 12,8(gam)$

\(n_{Fe}=\dfrac{m}{M}=\dfrac{16,8}{56}=0,3\left(mol\right)\\ PT:Fe+H_2SO_4\rightarrow FeSO_4+H_2\)

       0,3     0,3                        0,3 (mol)

a) V= n. 22,4 = 0,3 . 22,4 = 6,72(l)

 \(C\%=\dfrac{m_{H_2SO_4}}{m_{dd}}.100\%=\dfrac{0,3.98}{200}.100\%=11,76\%\)

b) PT: \(H_2+CuO\underrightarrow{t^o}Cu+H_2O\)

         0,3                0,3 

=> m_Cu=n.M=0,3.64=19,2(g)