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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 :
\(n_{Fe}=\dfrac{11.2}{56}=0.2\left(mol\right)\)
\(3Fe+2O_2\underrightarrow{t^0}Fe_3O_4\)
\(0.2.......0.3.......\dfrac{1}{15}\)
\(V_{O_2}=0.3\cdot22.4=6.72\left(l\right)\)
\(m_{Fe_3O_4}=\dfrac{1}{15}\cdot232=15.47\left(g\right)\)
\(n_{N_2}=\dfrac{2.8}{28}=0.1\left(mol\right)\)
\(2N_2+5O_2\underrightarrow{t^0}2N_2O_5\)
\(0.12......0.3........0.12\)
\(m_{N_2O_5}=0.12\cdot108=12.96\left(g\right)\)
a)
\(3Fe + 2O_2 \xrightarrow{t^o} Fe_3O_4\)
b)
Ta có :
\(n_{Fe} = \dfrac{8,4}{56} = 0,15(mol)\\ n_{O_2} = \dfrac{96}{32} = 3(mol)\)
Ta thấy : \(\dfrac{n_{Fe}}{3} = 0,05 < \dfrac{n_{O_2}}{2} = 1,5\) do đó O2 dư.
Theo PTHH :
\(n_{O_2\ pư} = \dfrac{2}{3}n_{Fe} = 0,1(mol)\\ \Rightarrow n_{O_2\ dư} = 3 - 0,1 = 2,9(mol)\\ \Rightarrow m_{O_2\ dư} = 92,8(gam)\)
c)
\(n_{Fe_3O_4} = \dfrac{1}{3}n_{Fe} = 0,05(mol)\\ \Rightarrow m_{Fe_3O_4} = 0,05.232 = 11,6(gam)\)
\(a)PTHH:FeCl_3+2O_2\xrightarrow[]{t^o}Fe_3O_4\)
mol 1 2 1
mol
\(b)\)Số mol \(FeCl_3\) là: \(n_{FeCl_3}=\dfrac{m_{FeCl_3}}{M_{FeCl_3}}=\dfrac{8,4}{162,5}=0,052\left(mol\right)\)
Số mol \(O_2\) là: \(n_{O_2}=\dfrac{m_{O_2}}{M_{O_2}}=\dfrac{96}{32}=3\left(mol\right)\)
Lập tỉ lệ: \(\dfrac{1}{0,052}>\dfrac{2}{3}\Rightarrow FeCl_3dư\)
Số mol \(FeCl_3\) phản ứng là:
Từ PTHH\(\Rightarrow\) \(n_{FeCl_3}=\dfrac{0,052\times3}{3}=0,035\left(mol\right)\)
Số mol \(FeCl_3\) dư là: \(n_{FeCl_3dư}=n_{FeCl_3đầu}-n_{FeCl_3p/ứng}=0,052-0,035=0,018\left(mol\right)\)
Khối lượng \(FeCl_3\) dư là: \(m_{FeCl_3dư}=n_{FeCl_3dư}\times M_{FeCl_3}=0,018\times162,5=2,925\left(g\right)\)
PTHH: \(Fe_2O_3+3H_2\underrightarrow{t^o}2Fe+3H_2O\)
a) Ta có: \(\left\{{}\begin{matrix}n_{H_2}=\dfrac{11,2}{22,4}=0,5\left(mol\right)\\n_{Fe_2O_3}=\dfrac{24}{160}=0,15\left(mol\right)\end{matrix}\right.\)
Xét tỉ lệ: \(\dfrac{0,15}{1}< \dfrac{0,5}{3}\) \(\Rightarrow\) Fe2O3 p/ứ hết, H2 còn dư
\(\Rightarrow n_{H_2\left(dư\right)}=0,05\left(mol\right)\)
b)
+) Cách 1
Theo PTHH: \(n_{Fe}=2n_{Fe_2O_3}=0,3\left(mol\right)\) \(\Rightarrow m_{Fe}=0,3\cdot56=16,8\left(g\right)\)
+) Cách 2:
Bảo toàn nguyên tố: \(n_{Fe}=2n_{Fe_2O_3}=....\)
nFe = 16.8/56 = 0.3 (mol)
nO2 = 6.72/22.4 = 0.3 (mol)
2Fe + 3O2 -to-> Fe3O4
0.2___0.3________0.1
mFe dư = ( 0.3 - 0.2 ) * 56 = 5.6 (g)
mFe3O4 = 0.1*232 = 23.2 (g)
a)
3Fe+2O2→Fe3O4
b)
nFe=16,8/56=0,3mol
nO2=6,72/22,4=0,3mol
Ta có: 0,3/3<0,3/2=> O2 dư tính theo Fe
nFe3O4=0,3/3=0,1
mFe3O4=0,1.232=23,2g
\(n_{Zn}=\dfrac{13}{65}=0.2\left(mol\right)\)
\(n_{O_2}=\dfrac{8.96}{22.4}=0.4\left(mol\right)\)
\(2Zn+O_2\underrightarrow{^{^{t^0}}}2ZnO\)
LTL : \(\dfrac{0.2}{2}< \dfrac{0.4}{1}\Rightarrow O_2dư\)
\(m_{O_2\left(dư\right)}=\left(0.4-0.1\right)\cdot32=9.6\left(g\right)\)
\(m_{ZnO}=0.2\cdot81=16.2\left(g\right)\)
Bài 3:
\(n_{H_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\)
a, PTHH: Fe3O4 + 4H2 --to--> 3Fe + 4H2O
0,1<------0,4
Zn + 2HCl ---> ZnCl2 + H2
0,4<-------------------------0,4
b, mFe3O4 = 0,1.232 = 23,2 (g)
c, mZn = 0,4.65 = 26 (g)
Bài 4:
\(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)
a, PTHH: Zn + 2HCl ---> ZnCl2 + H2
0,1---->0,2---------------->0,1
b, VH2 = 0,1.22,4 = 2,24 (l)
c, \(C_{M\left(HCl\right)}=\dfrac{0,2}{0,2}=1M\)
a ) \(n_{Fe_2O_4}=\frac{23,2}{232}=0,1\) mol
\(Fe_3O_4+4H_2\underrightarrow{t^0}3Fe+4H_2O\)
0,1 -> 0,4 -> 0,3
\(\Rightarrow n_{H_2}=4n_{Fe_3O_4}=0,4\) mol \(\Rightarrow V_{H_2}=0,4.22,4=8,96\) lít
b ) \(n_{Fe}=3n_{Fe_3O_4}=0,3\) mol \(\Rightarrow m_{Fe}=56.0,3=16,8\) gam.
\(n_{Zn}=\dfrac{3,25}{65}=0,05mol\)
\(Zn+2HCl\rightarrow ZnCl_2+H_2\)
0,05 0,1 0,05 ( mol )
\(V_{H_2}=0,05.22,4=1,12l\)
\(m_{HCl}=0,1.36,5=3,65g\)
\(Fe_3O_4+4H_2\rightarrow\left(t^o\right)3Fe+4H_2O\)
0,05 0,0375 ( mol )
\(m_{Fe}=0,0375.56=2,1g\)
\(a)3Fe+2O_2\rightarrow Fe_3O_4\)
\(3mol\) \(2mol\) \(1mol\)
\(0,3mol\) \(0,2mol\) \(0,1mol\)
\(b)n_{Fe}=\dfrac{m}{M}=\dfrac{16,8}{56}=0,3\left(mol\right)\)
\(n_{O_2}=\dfrac{V}{22,4}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)
\(\text{Ta thấy }O_2\text{ dư,}Fe\text{ phản ứng hết}\)
\(c)m_{Fe_3O_4}=n.M=0,1.232=23,2\left(g\right)\)
a) Fe3O4 + 4H2 --to--> 3Fe + 4H2O
b)
\(n_{H_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
\(n_{Fe_3O_4}=\dfrac{23,2}{232}=0,1\left(mol\right)\)
Xét tỉ lệ: \(\dfrac{0,1}{1}>\dfrac{0,1}{4}\) => H2 hết, Fe3O4 dư
PTHH: Fe3O4 + 4H2 --to--> 3Fe + 4H2O
0,025<--0,1------>0,075
=> \(m_{Fe_3O_4\left(dư\right)}=\left(0,1-0,025\right).232=17,4\left(g\right)\)
c) \(m_{Fe}=0,075.56=4,2\left(g\right)\)
ai giúp mik câu b với ạ