\(n_{AgNO_3}=0,2.0,4=0,08\left(mol\right)\)

\(n_{Zn}=\dfrac{3,9}{65}=0,06\left(mol\right)\)

Gọi số mol Cu ban đầu là a (mol)

Gọi số mol Cu pư là b (mol)

PTHH: Cu + 2AgNO₃ --> Cu(NO₃)₂ + 2Ag

             b------>2b--------->b--------->2b

=> Rắn sau pư chứa \(\left\{{}\begin{matrix}Cu:a-b\left(mol\right)\\Ag:2b\left(mol\right)\end{matrix}\right.\)

=> 64(a - b) + 108.2b = 7

=> 64a + 152b = 7 (1)

dd sau pư chứa \(\left\{{}\begin{matrix}Cu\left(NO_3\right)_2:b\left(mol\right)\\AgNO_3:0,08-2b\left(mol\right)\end{matrix}\right.\)

- Nếu Zn tan hết:

\(n_{Zn\left(NO_3\right)_2}=n_{Zn}=0,06\left(mol\right)\)

Mà \(n_{NO_3^-}=0,08\left(mol\right)\)

=> Vô lí

=> Zn không tan hết

PTHH: Zn + 2AgNO₃ --> Zn(NO₃)₂ + 2Ag

     (0,04-b)<-(0,08-2b)------------>(0,08-2b)

            Zn + Cu(NO₃)₂ --> Zn(NO₃)₂ + Cu

            b<-------b--------------------->b

=> Rắn sau pư gồm \(\left\{{}\begin{matrix}Ag:0,08-2b\left(mol\right)\\Cu:b\left(mol\right)\\Zn:0,02\left(mol\right)\end{matrix}\right.\)

=> 108(0,08 - 2b) + 64b + 0,02.65 = 6,14

=> b = 0,025 (mol)

=> a = 0,05 (mol)

m = 0,05.64 = 3,2 (g)

Em viết lại cho đúng đề nha

\(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\\ PTHH:Fe+H_2SO_{4\left(loãng\right)}\rightarrow FeSO_4+H_2\uparrow\left(1\right)\\ Fe+2H_2SO_{4\left(đặc\right)}\rightarrow FeSO_4+SO_2\uparrow+2H_2O\left(2\right)\\ 5SO_2+2H_2O+2KMnO_4\rightarrow2H_2SO_4+MnSO_4+K_2SO_4\left(3\right)\)

\(Theo.pt\left(1\right):n_{Fe}=n_{H_2}=0,2\left(mol\right)\\ Theo.pt\left(2\right):n_{Fe}=n_{SO_2}=0,2\left(mol\right)\\ Theo.pt\left(3\right):n_{KMnO_4}=\dfrac{2}{5}n_{SO_2}=\dfrac{2}{5}.0,2=0,08\left(mol\right)\)

\(\Rightarrow V=V_{SO_2}=0,2.22,4=4,48\left(l\right)\\ \Rightarrow V_{ddKMnO_4}=\dfrac{0,08}{2}=0,04\left(l\right)=40\left(ml\right)\)

đề thiếu

Ét ô Ét 

bài 2

Ta sục Br2

Chất làm mất màu C2H2

Chất ko hiện tg :CO2

C2H2+2Br2->C2H2Br4

Bài 3

CaC2+2H2O->Ca(OH)2+C2H2

C2H4+3O2-to>2CO2+2H2O

\(PTHH:C_2H_4+Br_2\rightarrow C_2H_4Br_2\)

\(n_{C_2H_4Br_2}=\frac{9,4}{188}=0,05\left(mol\right)\)

\(\Rightarrow n_{Br_2}=0,05\left(mol\right);n_{C_2H_4}=0,05\left(mol\right)\)

\(V_{Br_2}=0,05.22,4=1,12\left(l\right)\)

\(V_{C_2H_4}=0,05.22,4=1,12\left(l\right)\)

\(\%V_{C_2H_4}=\frac{1,12}{4,48}.100=25\%\)

\(\%V_{CH_4}=100\%-25\%=75\%\)

\(a,n_{C_2H_4Br_2}=\dfrac{9,4}{188}=0,05\left(mol\right)\\ PTHH:C_2H_4+Br_2\rightarrow C_2H_4Br_2\\ Mol:0,05\leftarrow0,05\leftarrow0,05\\ V_{Br_2}=\dfrac{0,05}{0,1}=0,5\left(l\right)=500\left(ml\right)\)

\(b,\%V_{C_2H_4}=\dfrac{0,05.22,4}{4,48}=25\%\\ \%V_{CH_4}=100\%-25\%=75\%\)

Đặt X có dạng CxHy

Theo bài ra, ta có: %C%H%C%H = 85,7100−85,785,7100−85,7

→ 12xy12xy= 85,714,385,714,3

→ y = 2x            

=> CTHH là C2H4 (thỏa mãn)  

=> Vậy ta chọn C. C2H4

Đặt \(X\)có dạng \(C_xH_y\)

Theo bài ra, ta có: \(\dfrac{\%C}{\%H}\) = \(\dfrac{85,7}{100-85,7}\)

 \(\Rightarrow\frac{12x}{y}\)\(=\)\(\dfrac{85,7}{14,3}\)

\(\Rightarrow y=2x\)         

\(\Rightarrow C_2H_4\)

Đáp án C 

\(n_{CH_4}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)

Gọi số mol C₂H₄, C₂H₂ là a, b (mol)

=> \(a+b=\dfrac{6,72}{22,4}-0,1=0,2\left(mol\right)\) (1)

\(n_{Br_2}=\dfrac{48}{160}=0,3\left(mol\right)\)

PTHH: C₂H₄ + Br₂ --> C₂H₄Br₂

               a--->a

            C₂H₂ + 2Br₂ --> C₂H₂Br₄

              b---->2b

=> a + 2b = 0,3 (2)

(1)(2) => a = 0,1 (mol); b = 0,1 (mol)

\(\%m_{CH_4}=\dfrac{0,1.16}{0,1.16+0,1.28+0,1.26}.100\%=22,857\%\)

\(\%m_{C_2H_4}=\dfrac{0,1.28}{0,1.16+0,1.28+0,1.26}.100\%=40\%\)

\(\%m_{C_2H_2}=\dfrac{0,1.26}{0,1.16+0,1.28+0,1.26}.100\%=37,143\%\)