Bài 1 :

a) \(2H_2 + O_2 \xrightarrow{t^o} 2H_2O\)

b)

\(n_{O_2} = \dfrac{1}{2}n_{H_2} = \dfrac{1}{2}. \dfrac{6,72}{22,4} = 0,15(mol)\\ \Rightarrow V_{O_2} = 0,15.22,4 = 3,36(lít)\\ \Rightarrow m_{O_2} = 0,15.32 = 4,8(gam)\)

Bài 2 :

\(2H_2 + O_2 \xrightarrow{t^o} 2H_2O\)

Vì  :\( \dfrac{n_{H_2}}{2} = \dfrac{8,4}{22,4.2} = 0,1875 > \dfrac{n_{O_2}}{1} = \dfrac{2,8}{22,4} =0,125\) nên Hidro dư

\(n_{H_2O} = 2n_{O_2} = 0,125.2 = 0,25(mol)\\ \Rightarrow m_{H_2O} = 0,25.18 = 4,5(gam)\)

2H₂+O₂-to>2H₂O

0,2-----0,1-------0,2 mol

n _H2O=\(\dfrac{3,6}{18}\)=0,2 mol

=>V_H2=0,2.22,4=4,48l

=>V_kk=0,1.22,4.5=11,2l

a. \(n_{H_2O}=\dfrac{3.6}{18}=0,2\left(mol\right)\)

PTHH : 2H₂ + O₂ -> 2H₂O

            0,2      0,1         0,2

b. \(V_{H_2}=0,2.22,4=4,48\left(l\right)\)

c. \(V_{O_2}=0,1.22,4-2,24\left(l\right)\)

\(V_{kk}=2,24.2=4,48\left(l\right)\)

\(n_{H_2}=\dfrac{2.8}{22.4}=0.125\left(mol\right)\)

\(2H_2+O_2\underrightarrow{^{t^0}}2H_2O\)

\(0.125..0.0625....0.125\)

\(m_{H_2}=0.125\cdot2=0.25\left(g\right)\)

\(m_{H_2O}=0.125\cdot18=2.25\left(g\right)\)

\(n_{H_2}=\dfrac{V_{H_2}}{22,4}=\dfrac{5,6}{22,4}=0,25mol\)

\(2H_2+O_2\rightarrow\left(t^o\right)2H_2O\)

0,25   0,125                               ( mol )

\(V_{O_2}=n_{O_2}.22,4=0,125.22,4=2,8l\)

4P+5O₂-to>2P₂O₅

0,4--0,5-----------0,2 mol

P₂O₅+3H₂O->2H₃PO₄

0,2------------------0,4

n O₂=\(\dfrac{11,2}{22,4}\)=0,5 mol

=>m _P=0,4.31=12,4g

=>m H_3PO4=0,4.98=39,2g

\(n_S=\dfrac{3.2}{32}=0.1\left(mol\right)\)

\(n_{O_2}=\dfrac{2.688}{22.4}=0.12\left(mol\right)\)

\(S+O_2\underrightarrow{t^0}SO_2\)

\(0.1...0.1.....01\)

\(V_{O_2\left(dư\right)}=\left(0.12-0.1\right)\cdot22.4=0.448\left(l\right)\)

\(V_{SO_2}=0.1\cdot22.4=2.24\left(l\right)\)

\(n_S=\dfrac{3,2}{32}=0,1\left(mol\right)\)

\(n_{O_2}=\dfrac{2,688}{22,4}=0,12\left(mol\right)\)

PTHH :                 \(S+O_2\rightarrow SO_2\)

Ban đầu :           0,1    0,12              (mol)

Phản ứng :        0,1    0,1      0,1     (mol)

Sau phản ứng :  0       0,02    0,1     (mol)

\(m_{O_2}=0,02.32=0,64\left(g\right)\)

\(m_{SO_2}=0,1.64=6,4\left(g\right)\)

\(V_{SO_2}=0,1.22,4=2,24\left(l\right)\)

nH2 = 6,72/22,4 = 0,3 (mol)

nCuO = 8/80 = 0,1 (mol)

PTHH: CuO + H2 -> (t°) Cu + H2O

LTL: 0,1 < 0,3 => H2 dư

nCu = nH2O = nCuO = 0,1 (mol)

mCu = 0,1 . 64 = 6,4 (g)

Số phân tử H2O: 0,1 . 6.10^23 = 0,6.10^23 (phân tử)

a. \(n_{H_2}=\dfrac{6.72}{22,4}=0,3\left(mol\right)\)

\(n_{CuO}=\dfrac{8}{80}=0,1\left(mol\right)\)

PTHH : CuO + H₂ -t^o-> Cu + H₂O

             0,1                   0,1      0,1

Xét tỉ lệ : 0,3 > 0,1 => H₂ dư , CuO đủ

b. \(m_{Cu}=0,1.64=6,4\left(g\right)\)

c. \(A=n.N=0,1.6.10^{23}=0,6.10^{23}\) phân tử 

\(n_{H_2O}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
\(2H_2+O_2\underrightarrow{t^o}2H_2O\)  
 0,2              0,2  
=> \(V_{H_2}=0,2.22,4=4,48\left(l\right)\\ \%V_{H_2}=\dfrac{4,48}{4,48+6,72}.100\%=40\%\\ \Rightarrow\%V_{O_2}=100\%-40\%=60\%\)

a) Fe₂O₃ + 3H₂ --t^o--> 2Fe + 3H₂O

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

\(n_{Fe_2O_3}=\dfrac{16}{160}=0,1\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,1}{1}=\dfrac{0,3}{3}\) => Pư vừa đủ

PTHH: Fe₂O₃ + 3H₂ --t^o--> 2Fe + 3H₂O

              0,1-------------->0,2

=> m_Fe = 0,2.56 = 11,2 (g)

c) pư vừa đủ thì sao dư đc :) ?

thanks