a, Giả sử: \(\left\{{}\begin{matrix}n_{Al}=x\left(mol\right)\\n_{Fe}=y\left(mol\right)\end{matrix}\right.\)

⇒ 27x + 56y = 13,8 (1)

BTNT Al và Fe, có: \(\left\{{}\begin{matrix}n_{Al_2O_3}=\dfrac{1}{2}n_{Al}=\dfrac{1}{2}x\left(mol\right)\\n_{Fe_3O_4}=\dfrac{1}{3}n_{Fe}=\dfrac{1}{3}y\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow\dfrac{1}{2}x.102+\dfrac{1}{3}y.232=21,8\left(g\right)\left(2\right)\)

Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}x=0,2\left(mol\right)\\y=0,15\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}\%m_{Al}=\dfrac{0,2.27}{13,8}.100\%\approx39,1\%\\\%m_{Fe}\approx60,9\%\end{matrix}\right.\)

b, BTNT O, có: \(n_{O_2}=\dfrac{3n_{Al_2O_3}+4n_{Fe_3O_4}}{2}=0,6\left(mol\right)\)

\(\Rightarrow V_{O_2}=0,6.22,4=13,44\left(l\right)\)

Bạn tham khảo nhé!

giúp tui với tui cần gấp

a. Ag không phản ứng nên ta có PTHH: \(2Mg+O_2\rightarrow^{t^o}2MgO\)

\(\rightarrow m_{O_2}=m_{hh}-m_{\mu\text{ối}}=18,8-15,6=3,2g\)

\(\rightarrow n_{O_2}=\frac{3,2}{32}=0,1mol\)

b. \(\rightarrow V_{O_2}=n.22,4=22,4.0,1=2,24l\)

\(\rightarrow V_{kk}=4,48.5=11,2l\)

c. Có \(n_{Mg}=2n_{O_2}=0,2l\)

\(\rightarrow m_{Mg}=0,2.24=4,8g\)

\(\rightarrow\%m_{Mg}=\frac{4,8.100}{15,6}\approx30,77\%\)

\(\rightarrow\%m_{Ag}=100\%-30,77\%=69,23\%\)

a) \(n_{CH_4}=\dfrac{1,12}{22,4}=0,05\left(mol\right)\)

\(n_{CO_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)

PTHH: CH₄ + 2O₂ --t^o--> CO₂ + 2H₂O

          0,05-->0,1------->0,05

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

            0,125<--0,3125<----0,25

=> \(\left\{{}\begin{matrix}\%V_{CH_4}=\dfrac{0,05}{0,05+0,125}.100\%=28,57\%\\\%V_{C_2H_2}=\dfrac{0,125}{0,05+0,125}.100\%=71,43\%\end{matrix}\right.\)

\(\left\{{}\begin{matrix}\%m_{CH_4}=\dfrac{0,05.16}{0,05.16+0,125.26}.100\%=19,753\%\\\%m_{C_2H_2}=\dfrac{0,125.26}{0,05.16+0,125.26}.100\%=80,247\%\end{matrix}\right.\)

b) \(n_{O_2}=0,1+0,3125=0,4125\left(mol\right)\)

=> \(V_{O_2}=0,4125.22,4=9,24\left(l\right)\)

=> V_kk = 9,24.5 = 46,2 (l)

a) Gọi số mol Al, Zn là 2a, a (mol)

PTHH: 4Al + 3O₂ --t^o--> 2Al₂O₃

          2a-->1,5a---------->a

             2Zn + O₂ --t^o--> 2ZnO

            a---->0,5a------->a

=> \(102a+81a=18,3\)

=> a = 0,1 (mol)

=> \(\left\{{}\begin{matrix}\%m_{Al}=\dfrac{0,2.27}{0,2.27+0,1.65}.100\%=45,378\%\\\%m_{Zn}=\dfrac{0,1.65}{0,2.27+0,1.65}.100\%=54,622\%\end{matrix}\right.\)

b) \(n_{O_2}=1,5a+0,5a=0,2\left(mol\right)\)

=> \(V_{O_2}=0,2.22,4=4,48\left(l\right)\)

Bài 1 :

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

\(4Na+O_2\rightarrow2Na_2O\)

..0,1....0,025....0,05.......

a, \(V_{O_2}=n.22,4=0,56\left(l\right)\)

b, \(m=m_{Na_2o}=n.M=3,1\left(g\right)\)

Bài 2 :

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

\(4Al+3O_2\rightarrow2Al_2O_3\)

..0,1...0,075...

\(\Rightarrow n_{O_2}=0,075\left(mol\right)\)

Mà : \(\Sigma n_{O_2}=\dfrac{V}{22,4}=0,4\left(mol\right)\)

\(\Rightarrow n_{O_2\left(Mg\right)}=0,4-0,075=0,325\left(mol\right)\)

\(2Mg+O_2\rightarrow2MgO\)

.0,65.....0,325........

\(\Rightarrow m_{Mg}=15,6\left(g\right)\)

\(\Rightarrow m_{hh}=2,7+15,6=18,3\left(g\right)\)

\(\Rightarrow\left\{{}\begin{matrix}\%Al=~14,75\\\%Mg=~85,25\end{matrix}\right.\) %

Bài 3 :

- Gọi số mol Al và Mg lần lượt là x , y

\(4Al+3O_2\rightarrow2Al_2O_3\)

..x....0,75x

\(2Mg+O_2\rightarrow2MgO\)

..y........0,5y...........

Có : \(n_{O_2}=0,75x+0,5y=\dfrac{V}{22,4}=0,1\left(mol\right)\left(I\right)\)

Lại có : \(m_{hh}=m_{Al}+m_{Mg}=27x+24y=3,9\left(II\right)\)

- Giair ( i ) và ( ii ) ta được : \(\left\{{}\begin{matrix}x=0,1\\y=0,05\end{matrix}\right.\) ( mol )

\(\Rightarrow\left\{{}\begin{matrix}\%Al=~69,23\\\%Mg=~30,77\end{matrix}\right.\) %

Vậy ...

a, \(CH_4+2O_2\underrightarrow{t^o}CO_2+2H_2O\)

\(2C_2H_2+5O_2\underrightarrow{t^o}4CO_2+2H_2O\)

Ta có: \(n_{CH_4}+n_{C_2H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\left(1\right)\)

\(n_{CO_2}=n_{CH_4}+2n_{C_2H_2}=\dfrac{7,84}{22,4}=0,35\left(mol\right)\left(2\right)\)

Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}n_{CH_4}=0,25\left(mol\right)\\n_{C_2H_2}=0,05\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}\%V_{CH_4}=\dfrac{0,25.22,4}{6,72}.100\%\approx83,33\%\\\%V_{C_2H_2}\approx16,67\%\end{matrix}\right.\)

Theo PT: \(n_{O_2}=2n_{CH_4}+\dfrac{5}{2}n_{C_2H_2}=0,625\left(mol\right)\Rightarrow m_{O_2}=0,625.32=20\left(g\right)\)