\(a,3Fe+2O_2\xrightarrow{t^o}Fe_3O_4\\ b,\text{Bảo toàn KL: }m_{Fe}+m_{O_2}=m_{Fe_3O_4}\\ c,m_{O_2}=m_{Fe_3O_4}-m_{Fe}=28,4-12,4=16(g)\)

Bài 1:

PT: \(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)

a, Ta có: \(n_{Fe}=\dfrac{5,6}{56}=0,1\left(mol\right)\)

\(n_{O_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,1}{3}< \dfrac{0,1}{2}\), ta được O₂ dư.

Theo PT: \(n_{O_2\left(pư\right)}=\dfrac{2}{3}n_{Fe}=\dfrac{1}{15}\left(mol\right)\)

\(\Rightarrow n_{O_2\left(dư\right)}=0,1-\dfrac{1}{15}=\dfrac{1}{30}\left(mol\right)\)

\(\Rightarrow\left\{{}\begin{matrix}m_{O_2\left(dư\right)}=\dfrac{1}{30}.32\approx1,067\left(g\right)\\V_{O_2\left(dư\right)}=\dfrac{1}{30}.2,24\approx0,746\left(l\right)\end{matrix}\right.\)

b, Theo PT: \(n_{Fe_3O_4}=\dfrac{1}{3}n_{Fe}=\dfrac{1}{30}\left(mol\right)\)

\(\Rightarrow m_{Fe_3O_4}=\dfrac{1}{30}.232\approx7,733\left(g\right)\)

Bài 2:

PT: \(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)

a, Ta có: \(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)

Theo PT: \(n_{Fe_3O_4}=\dfrac{1}{3}n_{Fe}=\dfrac{1}{15}\left(mol\right)\)

\(\Rightarrow m_{Fe_3O_4}=\dfrac{1}{15}.232\approx15,467\left(g\right)\)

b, Theo PT: \(n_{O_2}=\dfrac{2}{3}n_{Fe}=\dfrac{2}{15}\left(mol\right)\)

\(\Rightarrow V_{O_2}=\dfrac{2}{15}.22,4\approx2,9867\left(l\right)\)

c, PT: \(2N_2+5O_2\underrightarrow{t^o}2N_2O_5\)

Ta có: \(n_{N_2}=\dfrac{2,8}{28}=0,1\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,1}{2}>\dfrac{\dfrac{2}{15}}{5}\), ta được N₂ dư.

Theo PT: \(n_{N_2O_5}=\dfrac{2}{5}n_{O_2}=\dfrac{4}{75}\left(mol\right)\)

\(\Rightarrow m_{N_2O_5}=\dfrac{4}{75}.108=5,76\left(g\right)\)

Bạn tham khảo nhé!

Bài 1 : 

\(n_{Fe}=\dfrac{5.6}{56}=0.1\left(mol\right)\)

\(n_{O_2}=\dfrac{2.24}{224}=0.1\left(mol\right)\)

     \(3Fe+2O_2\underrightarrow{t^0}Fe_3O_4\)

\(Bđ:0.1......0.1\)

\(Pư:0.1.......\dfrac{1}{15}...\dfrac{1}{30}\)

\(Kt:0........\dfrac{1}{30}....\dfrac{1}{30}\)

\(V_{O_2\left(dư\right)}=\dfrac{1}{30}\cdot22.4=0.747\left(l\right)\)

\(m_{Fe_3O_4}=\dfrac{1}{30}\cdot232=7.73\left(g\right)\)

Bài 2 : 

\(n_{Fe}=\dfrac{11.2}{56}=0.2\left(mol\right)\)

\(3Fe+2O_2\underrightarrow{t^0}Fe_3O_4\)

\(0.2.......0.3.......\dfrac{1}{15}\)

\(V_{O_2}=0.3\cdot22.4=6.72\left(l\right)\)

\(m_{Fe_3O_4}=\dfrac{1}{15}\cdot232=15.47\left(g\right)\)

\(n_{N_2}=\dfrac{2.8}{28}=0.1\left(mol\right)\)

\(2N_2+5O_2\underrightarrow{t^0}2N_2O_5\)

\(0.12......0.3........0.12\)

\(m_{N_2O_5}=0.12\cdot108=12.96\left(g\right)\)

\(n_{Fe}=\dfrac{12.6}{56}=0.225\left(mol\right)\)

\(n_{O_2}=\dfrac{4.2}{22.4}=0.1875\left(mol\right)\)

\(3Fe+2O_2\underrightarrow{^{^{t^0}}}Fe_3O_4\)

\(3.........2\)

\(0.225......0.1875\)

Lập tỉ lệ : \(\dfrac{0.225}{3}< \dfrac{0.1875}{2}\Rightarrow O_2dư\)

\(m_{O_2\left(dư\right)}=\left(0.1875-0.225\cdot\dfrac{2}{3}\right)\cdot32=1.2\left(g\right)\)

\(m_{Fe_3O_4}=\dfrac{0.225}{3}\cdot232=17.4\left(g\right)\)

giup mink voi !!!

gap ah

 \(n_{Fe}=0,1\left(mol\right);n_{Cl_2}=0,12\left(mol\right)\)

\(2Fe+3Cl_2\rightarrow2FeCl_3\) (1)

Lập tỉ lệ : \(\dfrac{0,1}{2}>\dfrac{0,12}{3}\)

=> Sau phản ứng Fe dư

Hòa tan sản phẩm vào nước ta được:

2FeCl3 + Fe → 3FeCl2 (2)

b) Muối tạo thành là FeCl2 và FeCl3

\(n_{Fe\left(dư\right)}=0,1-0,12.\dfrac{2}{3}=0,02\left(mol\right)\)

\(n_{FeCl_2}=3n_{Fe\left(dư\right)}=0,06\left(mol\right)\)

Ta có : \(n_{FeCl_3}=n_{FeCl_3\left(1\right)}-n_{FeCl_3\left(2\right)}=0,12.\dfrac{2}{3}-0,02.2=0,04\left(mol\right)\)

\(m_{FeCl_2}=0,06.127=7,62\left(g\right)\)

\(m_{FeCl_3}=0,04.162,5=6,5\left(g\right)\)

c) \(CM_{FeCl_2}=\dfrac{0,06}{0,5}=0,12M\)

\(CM_{FeCl_3}=\dfrac{0,04}{0,5}=0,08M\)

Bài 1:

\(a,2Cu+O_2\underrightarrow{t^o}2CuO\)

b, \(n_{O_2}=\dfrac{1,12}{32}=0,035mol\)

\(n_{Cu}=\dfrac{6,4}{64}=0,1mol\)

\(\dfrac{0,1}{2}>\dfrac{0,035}{1}\) => Cu dư, O₂ đủ

\(n_{Cu}\left(dư\right)=0,1-0,07=0,039\left(mol\right)\)

c, \(m_{CuO}=0,07.80=5,6g\)

Bài 2:

\(n_{Al}=\dfrac{13,5}{27}=0,5mol\)

\(n_{O_2}=\dfrac{6,67}{32}=0,21\left(mol\right)\)

\(4Al+3O_2\underrightarrow{t^o}2Al_2O_3\)

\(\dfrac{0,5}{4}>\dfrac{0,21}{3}\) => Al dư, O₂ đủ

\(n_{Al_2O_3}=\dfrac{2}{3}.0,21=0,14\left(mol\right)\)

\(m_{Al_2O_3}=0,14.102=14,28g\)

a) 3Fe + 2O₂ --t^o--> Fe₃O₄

Sô nguyên tử Fe: số phân tử O₂ : số phân tử Fe₃O₄ = 3:2:1

b) \(n_{Fe}=\dfrac{25,2}{56}=0,45\left(mol\right)\)

3Fe + 2O₂ --t^o--> Fe₃O₄

0,45->0,3--------->0,15

=> m_Fe3O4 = 0,15.232 = 34,8 (g)

=> V_O2 = 0,3.22,4 = 6,72(l)

Fe+2HCl->FeCl₂+H₂

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

2H2+O₂-to>2H₂O

0,1----0,05 mol

0,1--0,1

n _Fe=\(\dfrac{5,6}{56}\)=0,1 mol

=>V_H2=0,1.22,4=2,24l

=>m_kk=0,05.29=1,45l

Không đủ dữ kiện tính $m_{kk}$ mà chỉ tính được $V_{kk}$

$a)PTHH:Fe+2HCl\to FeCl_2+H_2\uparrow$

$\to$ Phản ứng trao đổi

$b)n_{Fe}=\dfrac{5,6}{56}=0,1(mol)$

Theo PT: $n_{H_2}=n_{Fe}=0,1(mol)$

$\Rightarrow V_{H_2(đktc)}=0,1.22,4=2,24(lít)$

$c)PTHH:2H_2+O_2\xrightarrow{t^o}2H_2O$

Theo PT: $n_{O_2}=\dfrac{1}{2}n_{H_2}=0,05(mol)$

$\Rightarrow V_{O_2(đktc)}=0,05.22,4=1,12(lít)$

Mà $V_{O_2}$ chiếm $20\%$ của $V_{kk}$

$\Rightarrow V_{kk(đktc)}=\dfrac{1,12}{20\%}=5,6(lít)$

\(n_{H_2}=\dfrac{13,44}{22,4}=0,6mol\)

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

0,6       0,3                  0,6        ( mol )

\(m_{H_2O}=0,6.18=10,8g\)

\(V_{kk}=V_{O_2}.5=\left(0,3.22,4\right).5=33,6l\)