2. \(1.n_{H_2}=0,1\left(mol\right);n_{CuO}=0,15\left(mol\right)\\ H_2+CuO-^{t^o}\rightarrow Cu+H_2O\\ LTL:\dfrac{0,1}{1}< \dfrac{0,15}{1}\Rightarrow CuOdư\\ n_{CuO\left(pư\right)}=n_{H_2}=0,1\left(mol\right)\\ n_{CuO\left(dư\right)}=0,15-0,1=0,05\left(mol\right)\\ \Rightarrow m_{CuO\left(dư\right)}=4\left(g\right)\\ 2.n_{H_@}=n_{Cu}=0,1\left(mol\right)\\ \Rightarrow m_{Cu}=0,1.64=6,4\left(g\right)\)

Bài 9:

Gọi hóa trị của M là x(x>0)

\(n_{H_2}=\dfrac{1,008}{22,4}=0,045(mol)\\ \text {Bảo toàn O: }n_{O/oxit}=n_{H_2}=\dfrac{1,344}{22,4}=0,06(mol)\\ \Rightarrow m_{M}=m_{oxit}-m_{O_2}=3,48-0,06.16=2,52(g)\\ PTHH:2M+2xHCl\to 2MCl_x+xH_2\\ \Rightarrow n_{M}=\dfrac{2.0,045}{x}=\dfrac{0,09}{x}\\ \Rightarrow M_{M}=\dfrac{2,52}{\dfrac{0,09}{x}}=28x\)

Thay \(x=2\Rightarrow M_M=56(Fe)\)

\(\Rightarrow n_{Fe}=\dfrac{2,52}{56}=0,045(mol)\\ \Rightarrow \dfrac{n_{Fe}}{n_{O}}=\dfrac{0,045}{0,06}=\dfrac{3}{4}\)

Vậy M là sắt (Fe) và CTHH oxit là \(Fe_3O_4\)

9. Tham khảo

Bài 12:

\(\text{Đ}\text{ặt}:X\left(a\right)\left(x:nguy\text{ê}n,d\text{ư}\text{ơn}g\right)\\ 2X+2aHCl\rightarrow2XCl_a+H_2\\ n_{H_2}=\dfrac{4,704}{22,4}=0,21\left(mol\right)\\ \Rightarrow n_X=0,21.2=0,42\left(mol\right)\\ M_X=\dfrac{3,78}{0,42}=9\left(\dfrac{g}{mol}\right)\\ \Rightarrow X:B\text{er}i\left(Be=9\right)\)

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Bài 11:

\(m_{r\text{ắn}\left(gi\text{ảm}\right)}=m_{O\left(trong.\text{ox}it\right)}=4,8\left(g\right)\\ \Rightarrow n_{O\left(trong.\text{ox}it\right)}=\dfrac{4,8}{16}=0,3\left(mol\right)\\ n_{Fe}=\dfrac{16-4,8}{56}=0,2\left(mol\right)\\ \text{Đ}\text{ặt}.CTTQ:Fe_xO_y\left(x,y:nguy\text{ên},d\text{ư}\text{ơ}ng\right)\\ x:y=0,2:0,3=2:3\\ \Rightarrow x=0,2;y=0,3\\ \Rightarrow CTHH:Fe_2O_3\)

\(n_P=\dfrac{6,2}{31}=0,2\left(mol\right)\\ n_{O_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\\ PTHH:4P+5O_2\underrightarrow{t^o}2P_2O_5\\ LTL:\dfrac{0,2}{4}< \dfrac{0,4}{5}\Rightarrow O_2dư\)

\(n_{O_2\left(pư\right)}=\dfrac{5}{4}n_P=\dfrac{5}{4}.0,2=0,25\left(mol\right)\\ n_{O_2\left(dư\right)}=0,4-0,25=0,15\left(mol\right)\)

\(n_{P_2O_5\left(lt\right)}=\dfrac{1}{2}n_P=\dfrac{1}{2}.0,2=0,1\left(mol\right)\\ m_{P_2O_5\left(lt\right)}=0,1.142=14,2\left(g\right)\\ m_{P_2O_5\left(tt\right)}=0,1.142.80\%=11,36\left(g\right)\)

H2+CuO-to>Cu+H2O

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

n H2=0,1 mol

n CuO=0,15 mol

=>m Cu=0,1.64=6,4g

=>m CuO=0,05.80=4g

B

\(n_{H_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\\ n_{CuO}=\dfrac{12}{80}=0,15\left(mol\right)\\ pthh:CuO+H_2\underrightarrow{t^o}Cu+H_2O\\ LTL:\dfrac{0,1}{1}< \dfrac{0,15}{1}\\ =>CuO\left(d\right)\\ n_{CuO\left(pu\right)}=n_{Cu}=n_{H_2}=0,1\left(mol\right)\\ \Rightarrow\left\{{}\begin{matrix}m_{Cu}=0,1.64=6,4\left(g\right)\\m_{CuO\left(d\right)}=\left(0,15-0,1\right).80=4\end{matrix}\right.\\ =>B\)

a) \(n_{Br_2}=\dfrac{32}{160}=0,2\left(mol\right)\)

PTHH: C₂H₂ + 2Br₂ --> C₂H₂Br₄

            0,1<-----0,2

=> m_C2H2 = 0,1.26 =2,6 (g)

\(\%m_{C_2H_2}=\dfrac{2,6}{8}.100\%=32,5\%\)

\(\%m_{CH_4}=\dfrac{8-2,6}{8}.100\%=67,5\%\)

b) \(n_{CH_4}=\dfrac{8-2,6}{16}=0,3375\left(mol\right)\)
PTHH: CH₄ + 2O₂ --t^o--> CO₂ + 2H₂O

        0,3375->0,675 

            2C₂H₂ + 5O₂ --t^o--> 4CO₂ + 2H₂O

              0,1---->0,25

=> V_O2 = (0,675 + 0,25).22,4 = 20,72 (l)

=> V_kk = 20,72.5 = 103,6 (l)

refer

Gọi x, y lần lượt là số mol của C₂H₄, C₂H₂ ( x, y > 0 )

n_Br2 = 0,2 mol

C₂H₄ + Br₂ → C₂H₄Br₂

x............x...............x

C₂H₂ + 2Br₂ → C₂H₂Br₄

y.............2y..............y

Ta có hệ

{28x+26y=4,1x+2y=0,2{28x+26y=4,1x+2y=0,2

⇒ {x=0,1y=0,05{x=0,1y=0,05

⇒ %_C2H4 =   31,7%

C₂H₄ + 3O₂ ---t^o---> 2CO₂ + 2H₂O

0,1.........0,3

⇒ VO2 = 0,3.22,4 = 6,72 (l)

2C₂H₂ + 5O₂ ---t^o---> 4CO₂ + 2H₂O

0,05.......0,125

⇒ VO2 = 0,125.22,4 = 2,8 (l)

⇒ _VO2 = 6,72 + 2,8 = 9,52 (l)

a.\(n_{Br_2}=\dfrac{32}{160}=0,2mol\)

\(C_2H_2+2Br_2\rightarrow C_2H_2Br_4\)

  0,1       0,2                          ( mol )

\(m_{C_2H_2}=0,1.26=2,6g\)

\(\%m_{C_2H_2}=\dfrac{2,6}{8}.100=32,5\%\)

\(\%m_{CH_4}=100\%-32,5\%=67,5\%\)

b.\(2C_2H_2+5O_2\rightarrow\left(t^o\right)4CO_2+2H_2O\)

      0,1       0,25                                     ( mol )

\(n_{CH_4}=\dfrac{8-2,6}{16}=0,3375mol\)

\(CH_4+2O_2\rightarrow\left(t^o\right)CO_2+2H_2O\)

 0,3375  0,675                                 ( mol )

\(V_{kk}=\left(0,25+0,675\right).22,4.5=103,6l\)              

\(a,PTHH:Fe_3O_4+4H_2\xrightarrow{t^o}3Fe+4H_2O\\ n_{H_2}=\dfrac{6,72}{22,4}=0,3(mol);n_{Fe_3O_4}=\dfrac{46,4}{232}=0,2(mol)\)

Vì \(\dfrac{n_{H_2}}{4}<\dfrac{n_{Fe_3O_4}}{1}\) nên \(Fe_3O_4\) dư

\(n_{Fe_3O_4(dư)}=0,2-\dfrac{0,3}{4}=0,125(mol)\\ \Rightarrow m_{Fe_3O_4(dư)}=0,125.232=29(g)\\ b,n_{Fe}=\dfrac{3}{4}n_{H_2}=0,225(mol)\\ \Rightarrow m_{Fe}=0,225.56=12,6(g)\)

\(a,PTHH:4Al+3O_2\underrightarrow{t^o}2Al_2O_3\\ n_{Al}=\dfrac{m}{M}=\dfrac{10,8}{27}=0,4\left(mol\right)\\ Theo.PTHH:n_{Al_2O_3}=\dfrac{1}{2}.n_{Al}=\dfrac{1}{2}.0,4=0,2\left(mol\right)\\ m_{Al_2O_3}=n.M=0,2.102=20,4\left(g\right)\)

\(b,n_{O_2}=\dfrac{V_{\left(đktc\right)}}{22,4}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\\ Lập.tỉ.lệ:\dfrac{n_{Al}}{4}>\dfrac{n_{O_2}}{3}\Rightarrow Al.dư\\ Theo.PTHH:n_{Al\left(pư\right)}=\dfrac{4}{3}.n_{O_2}=\dfrac{4}{3}.0,2\left(mol\right)\\ n_{Al\left(dư\right)}=n_{Al\left(bđ\right)}-n_{Al\left(pư\right)}=0,4-0,2=0,2\left(mol\right)\\ Theo.PTHH:n_{Al_2O_3}=\dfrac{1}{2}.n_{Al}=\dfrac{1}{2}.0,2=0,1\left(mol\right)\\ m_{Al_2O_3}=n.M=0,1=102=10,2\left(g\right)\)

Đáp án C

Ta có n_{O bị lấy đi bởi CO} =  = 0,5 mol

⇒ n_{CO pứ} = n_O = 0,5 mol

Bảo toàn e cả quá trình ta có: 2n_CO = 2n_H2 Û n_H2 = n_CO = 0,5 mol

⇒ V_H2 = 0,5 × 22,4 = 11,2 lít