lỗi

\(n_{O_2}=\dfrac{3,36}{22,4}=0,15mol\)

Gọi \(\left\{{}\begin{matrix}n_C=x\\n_S=y\end{matrix}\right.\)

\(C+O_2\rightarrow\left(t^o\right)CO_2\)

x      x                          ( mol )

\(S+O_2\rightarrow\left(t^o\right)SO_2\)

 y     y                            ( mol )

Ta có:

\(\left\{{}\begin{matrix}12x+32y=2,8\\x+y=0,15\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=0,1\\y=0,05\end{matrix}\right.\)

\(\rightarrow m_C=0,1.12=1,2g\)

\(\rightarrow m_S=0,05.32=1,6g\)

\(\rightarrow\left\{{}\begin{matrix}\%m_C=\dfrac{1,2}{2,8}.100=42,85\%\\\%m_S=100\%-42,85\%=57,15\%\end{matrix}\right.\)

Gọi \(\left\{{}\begin{matrix}n_C=a\left(mol\right)\\n_S=b\left(mol\right)\end{matrix}\right.\left(a,b>0\right)\)

PTHH:

C + O₂ --t^o--> CO₂

a--->a

S + O₂ --t^o--> SO₂

b--->b

=> \(\left\{{}\begin{matrix}12a+32b=2,8\\a+b=\dfrac{3,36}{22,4}=0,15\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,1\left(mol\right)\\b=0,05\left(mol\right)\end{matrix}\right.\left(TM\right)\)

\(\Rightarrow\left\{{}\begin{matrix}m_C=0,1.12=1,2\left(g\right)\\m_S=0,05.32=1,6\left(g\right)\end{matrix}\right.\)

Bài 14: Đốt cháy hoàn toàn một hỗn hợp khí gồm có CO và H₂ cần dùng 6,72 lit khí O₂. Khí sinh ra có 4,48 lit khí CO₂. Hãy tính thành phần % của hỗn hợp khí ban đầu theo thể tích hỗn hợp( các thể tích khí đều đo ở cùng đktc)

PTHH: \(C+O_2\xrightarrow[]{t^o}CO_2\)

              a___a______a    (mol)

            \(S+O_2\xrightarrow[]{t^o}SO_2\)

             b___b_______b   (mol)

Ta lập HPT: \(\left\{{}\begin{matrix}12a+32b=10\\a+b=\dfrac{11,2}{22,4}=0,5\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}a=0,3\\b=0,2\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}m_C=0,3\cdot12=3,6\left(g\right)\\m_S=6,4\left(g\right)\\V_{khí}=0,5\cdot22,4=11,2\left(l\right)\end{matrix}\right.\)

Tương tự:

https://hoc24.vn/cau-hoi/2-de-dot-chay-het-132-gam-hon-hop-gom-bot-fe-va-mg-can-dung-het-448-lit-khio2-dktc-tao-ra-san-pham-la-fe3o4-va-mgo-theo-phan-ungfe-o2-to-fe.3025810936660

\(n_{Al} = a ; n_{Fe} = b\Rightarrow 27a + 56b = 27,6(1)\\ 4Al + 3O_2 \xrightarrow{t^o} 2Al_2O_3\\ 3Fe + 2O_2 \xrightarrow{t^o} Fe_3O_4\\ n_{Al_2O_3} = \dfrac{1}{2}n_{Al} = 0,5a(mol)\\ n_{Fe_3O_4} = \dfrac{1}{3}n_{Fe} = \dfrac{b}{3}(mol)\\ \Rightarrow 0,5a.102 + \dfrac{b}{3}232 = 43,6(2)\\ (1)(2) \Rightarrow a = 0,4 ; b = 0,3\\ m_{Al} = 0,4.27 = 10,8(gam) ; m_{Fe} = 0,3.56 = 16,8(gam)\)

Đặt \(\left\{{}\begin{matrix}n_{Al}=x\left(mol\right)\\n_{Fe}=y\left(mol\right)\end{matrix}\right.\)

Theo đề: \(m_{hh}=39\left(g\right)\)

\(\Rightarrow m_{Al}+m_{Fe}=39\\ \Rightarrow27x+56y=39\left(1\right)\)

\(PTHH:4Al+3O_2\underrightarrow{t^o}2Al_2O_3\\ \left(mol\right)....x\rightarrow..0.75x....0,5x\\ PTHH:3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\\ \left(mol\right)....y\rightarrow..\dfrac{2}{3}y.....\dfrac{1}{3}y\)

Theo đề: \(n_{O_2}=\dfrac{V}{22,4}=\dfrac{12,32}{22,4}=0,55\left(mol\right)\)

\(\Rightarrow0,75x+\dfrac{2}{3}y=0,55\left(2\right)\)

\(\xrightarrow[\left(1\right)]{\left(2\right)}\left\{{}\begin{matrix}27x+56y=39\\0,75x+\dfrac{2}{3}y=0,55\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}x=0,2\\y=0,6\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}m_{Al}=0,2.27=5,4\left(g\right)\\m_{Fe}=0,6.56=33,6\left(g\right)\end{matrix}\right.\\ m_r=m_{Al_2O_3}+m_{Fe_3O_4}=0,5.0,2.102+\dfrac{1}{3}.0,6.232=56,6\left(g\right)\)

2,8 hay 28 

số liệu phải là 2,8 g hh nhé

C+O₂-to>CO₂

x-----x

S+O₂-to>SO₂

y----y

Ta có :\(\left\{{}\begin{matrix}12x+32y=2,8\\x+y=0,15\end{matrix}\right.\)

=>x=0,1 mol, y=0,05 mol

=>%m_C=\(\dfrac{0,1.12}{2,8}.100=42,86\%\)

=>%m_S=100-42,86=57,14%

Gọi nC = a (mol); nS = b (mol)

12a + 32b = 2,8 (g) (1)

nO2 = 3,36/22,4 = 0,15 (mol)

PTHH:

C + O2 -> (t°) CO2

Mol: a ---> a

S + O2 -> (t°) SO2

Mol: b ---> b

a + b = 0,15 (mol) (2)

Từ (1), (2) => a = 0,1 (mol); b = 0,05 (mol)

mC = 0,1 . 12 = 1,2 (g)

%mC = 1,2/2,8 = 42,85%