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Đặt \(\left\{{}\begin{matrix}n_{Mg}=x\left(mol\right)\\n_{Fe}=y\left(mol\right)\end{matrix}\right.\)
Theo đề: \(m_{hh}=36\left(g\right)\)
\(\Rightarrow m_{Mg}+m_{Fe}=36\\ \Rightarrow24x+56y=36\left(1\right)\)
\(PTHH:2Mg+O_2\underrightarrow{t^o}2MgO\\ \left(mol\right)....x\rightarrow...0,5x.....x\\ PTHH:3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\\ \left(mol\right)....y\rightarrow...\dfrac{2}{3}y....\dfrac{1}{3}y\)
Theo đề: \(n_{O_2}=\dfrac{13,44}{22,4}=0,6\left(mol\right)\)
\(\Rightarrow0,5x+\dfrac{2}{3}y=0,6\left(2\right)\)
\(\xrightarrow[\left(2\right)]{\left(1\right)}\left\{{}\begin{matrix}24x+56y=36\\0,5x+\dfrac{2}{3}y=0,6\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}x=0,8\\y=0,3\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}m_{Mg}=0,8.24=19,2\left(g\right)\\m_{Fe}=0,3.56=16,8\left(g\right)\end{matrix}\right.\\ m_r=m_{MgO}+m_{Fe_3O_4}=0,8.40+\dfrac{1}{3}.0,3.232=55,2\left(g\right)\)
PTHH: C+O2→CO20,3mol:0,3mol→0,3molC+O2→CO20,3mol:0,3mol→0,3mol
S+O2→SO20,2mol:0,2mol→0,2molS+O2→SO20,2mol:0,2mol→0,2mol
mC=36%10100%=3,6(g)⇔nC=3,612=0,3(mol)mC=36%10100%=3,6(g)⇔nC=3,612=0,3(mol)
mS=10−3,6=6,4(g)⇔nS=6,432=0,2(mol)mS=10−3,6=6,4(g)⇔nS=6,432=0,2(mol)
VO2=(0,3+0,2)22,4=11,2(l)VO2=(0,3+0,2)22,4=11,2(l)
mhh=mCO2+mSO2=0,3.44+0,2.64=26(g)
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: \(\left\{{}\begin{matrix}12a+32b=10\\a+b=\dfrac{11,2}{22,4}=0,5\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}a=0,3\\b=0,2\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}m_C=0,3\cdot12=3,6\left(g\right)\\m_S=6,4\left(g\right)\\V_{khí}=0,5\cdot22,4=11,2\left(l\right)\end{matrix}\right.\)
a: \(C+O_2\rightarrow CO_2\)(ĐK: t độ)
x x x
\(S+O_2\rightarrow SO_2\)(ĐK: t độ)
y y y
b: \(n_{O_2}=\dfrac{11.2}{22.4}=0.5\left(mol\right)\)
Theo đề, ta có hệ:
12x+32y=10 và x+y=0,5
=>x=0,3 và y=0,2
\(m_C=0.3\cdot12=3.6\left(g\right)\)
\(m_S=0.2\cdot32=6.4\left(g\right)\)
c: \(n_{CO_2}=n_C=0.3\left(mol\right)\)
\(n_{SO_2}=n_S=0.2\left(mol\right)\)
\(V_{khí}=22.4\left(0.3+0.2\right)=11.2\left(lít\right)\)
\(n_{O_2}=\dfrac{11,2}{22,4}=0,5\left(mol\right)\)
PTHH :
\(C+O_2\rightarrow\left(t^o\right)CO_2\)
x x x
\(S+O_2\rightarrow\left(t^o\right)SO_2\)
y y y
Gọi n C = x
n S = y (mol)
Ta có hệ PT :
\(\left\{{}\begin{matrix}12x+32y=10\\x+y=0,5\end{matrix}\right.\)
\(\rightarrow x=0,3;y=0,2\)
\(m_C=0,3.12=3,6\left(g\right)\)
\(m_S=0,2.32=6,4\left(g\right)\)
\(c,V_{hhk}=\left(0,3+0,2\right).22,4=11,2\left(l\right)\)
a) PTHH: 2Al + 6 HCl -> 2 AlCl3 + 3 H2
x___________3x______________1,5x(mol)
Fe +2 HCl -> FeCl2 + H2
y___2y____y______y(mol)
b) Ta có: m(rắn)= mCu=0,4(g)
=> m(Al, Fe)=1,5-mCu=1,5-0,4=1,1(g)
nH2= 0,04(mol)
Ta lập hpt:
\(\left\{{}\begin{matrix}27x+56y=1,1\\1,5x+y=0,04\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0,02\\y=0,01\end{matrix}\right.\)
=> mAl=27.0,02=0,54(g)
mFe=56.0,01=0,56(g)
PTHH:
\(CaCO_3+2HCl\rightarrow CaCl_2+H_2O+CO_2\uparrow\)
0,15 0,15
\(CaO+2HCl\rightarrow CaCl_2+H_2O\)
Ta có: \(n_{CO_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
\(\Rightarrow m_{CaCO_3}=0,15\cdot100=15\left(g\right)\)
\(\Rightarrow m_{CaO}=20,6-15=5,6\left(g\right)\)
\(\Rightarrow\%m_{CaCO_3}=\dfrac{15\cdot100}{20,6}\approx73\%\)
\(\Rightarrow\%m_{CaO}=100\%-73\%=27\%\)
\(n_{P_2O_5}=\dfrac{28,4}{142}=0,2\left(mol\right)\)
\(n_{SO_2}=\dfrac{5,6}{22,4}=0,25\left(mol\right)\)
PTHH: 4P + 5O2 --to--> 2P2O5
0,4<--------------0,2
S + O2 --to--> SO2
0,25<----------0,25
=> \(\left\{{}\begin{matrix}\%m_P=\dfrac{0,4.31}{0,4.31+0,25.32}.100\%=60,78\%\\\%m_S=\dfrac{0,25.32}{0,4.31+0,25.32}.100\%=39,22\%\end{matrix}\right.\)
\(m_{Al}=19,2\%.27,8=5,3376\left(g\right)\Rightarrow n_{Al}=0,2\left(mol\right)\)
\(m_{Fe}=27,8-5,3376=22,4624\left(g\right)\Rightarrow n_{Fe}=0,4\left(mol\right)\)
\(4Al+3O_2-^{t^o}\rightarrow2Al_2O_3\)
\(3Fe+2O_2-^{t^o}\rightarrow Fe_3O_4\)
Theo PT : \(n_{O_2}=0,2.\dfrac{3}{4}+0,4.\dfrac{2}{3}=\dfrac{5}{12}\left(mol\right)\)
Vì oxi chiếm 20% thể tích không khí
=> \(V_{kk}=\dfrac{5}{12}.22,4.\dfrac{100}{20}=\dfrac{140}{3}\left(lít\right)=46,67\left(lít\right)\)
Bảo toàn khối lượng ta có: \(m_{KL}+m_{O_2}=m_{oxit}\)
=> \(m_{oxit}=27,8+\dfrac{5}{12}.32=\dfrac{617}{15}\left(g\right)=41,13\left(g\right)\)
a,
mAl=27,8.19,42%=5,4gmAl=27,8.19,42%=5,4g
⇒nAl=5,427=0,2mol⇒nAl=5,427=0,2mol
⇒nFe=27,8−5,456=0,4mol⇒nFe=27,8−5,456=0,4mol
4Al+3O2to→2Al2O34Al+3O2→to2Al2O3
3Fe+2O2to→Fe3O43Fe+2O2→toFe3O4
⇒nO2=34nAl+23nFe=512mol⇒nO2=34nAl+23nFe=512mol
⇒Vkk=512.22,4.5=46,67l⇒Vkk=512.22,4.5=46,67l
b,
mrắn=27,8+mO2=27,8+512.32=41,1g
\(n_{Fe} = a(mol) ; n_{Mg} = b(mol)\\ \Rightarrow 56a + 24b = 16,8 - 6,4 = 10,4(1)\\ Fe + 2HCl \to FeCl_2 + H_2\\ Mg + 2HCl \to MgCl_2 + H_2\\ n_{H_2} = a + b = \dfrac{6,72}{22,4} = 0,3(2)\)
Từ (1)(2) suy ra: a = 0,1 ; b = 0,2
Vậy :
\(\%m_{Fe} = \dfrac{0,1.56}{16,8}.100\% = 33,33\%\\ \%m_{Mg} = \dfrac{0,2.24}{16,8}.100\% = 28,57\%\\ \%m_{Cu} = 100\% - 33,33\% - 28,57\% = 38,1\%\)
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: \(n_{O_2}=\dfrac{V}{22,4}=\dfrac{12,32}{22,4}=0,55\left(mol\right)\)
\(\Rightarrow0,75x+\dfrac{2}{3}y=0,55\left(2\right)\)
\(\xrightarrow[\left(1\right)]{\left(2\right)}\left\{{}\begin{matrix}27x+56y=39\\0,75x+\dfrac{2}{3}y=0,55\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}x=0,2\\y=0,6\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}m_{Al}=0,2.27=5,4\left(g\right)\\m_{Fe}=0,6.56=33,6\left(g\right)\end{matrix}\right.\\ m_r=m_{Al_2O_3}+m_{Fe_3O_4}=0,5.0,2.102+\dfrac{1}{3}.0,6.232=56,6\left(g\right)\)