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a, Ta có : \(\dfrac{n_{Al}}{n_{Mg}}=\dfrac{2}{1}\)
Mà \(m_{hh}=m_{Al}+m_{Mg}=27n_{Al}+24n_{Mg}=7,8\)
\(\Rightarrow\left\{{}\begin{matrix}n_{Al}=0,2\\n_{Mg}=0,1\end{matrix}\right.\) mol
b, Ta có : \(\left\{{}\begin{matrix}m_{Al}=n.M=5,4\\m_{Mg}=n.M=2,4\end{matrix}\right.\) g
Vậy ...
\(n_{H_2SO_4}=5a\left(mol\right),n_{HCl}=3a\left(mol\right)\)
\(m=98\cdot5a+36.5\cdot3a=5.995\left(g\right)\)
\(\Rightarrow a=0.01\)
\(n_{H_2SO_4}=0.05\left(mol\right),n_{HCl}=0.03\left(mol\right)\)
\(b.\)
\(n_{H_2SO_4}=0.025\left(mol\right),n_{HCl}=0.015\left(mol\right)\)
\(n_{CO}=x\left(mol\right),n_{CO_2}=y\left(mol\right)\)
\(n_B=x+y=0.025+0.015=0.04\left(mol\right)\left(1\right)\)
\(m_B=28x+44y=2.16\left(g\right)\left(2\right)\)
\(\left(1\right),\left(2\right):\) Không biết sao tới chổ này số mol âm mất em ơii
\(\left\{{}\begin{matrix}n_{Cl_2}+n_{O_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\\\dfrac{n_{Cl_2}}{n_{O_2}}=\dfrac{1}{3}\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}n_{Cl_2}=0,1\left(mol\right)\\n_{O_2}=0,3\left(mol\right)\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}m_{Cl_2}=0,1.71=7,1\left(g\right)\\m_{O_2}=0,3.32=9,6\left(g\right)\end{matrix}\right.\)
=> mhh = 7,1 + 9,6 = 16,7(g)
Đặt $n_{Cl_2}=x(mol)\Rightarrow n_{O_2}=3x(mol)$
Mà $n_{hh}=n_{Cl_2}+n_{O_2}=\dfrac{8,96}{22,4}=0,4$
$\Rightarrow x+3x=0,4\Rightarrow x=0,1$
$\Rightarrow m_{Cl_2}=0,1.71=7,1(g);m_{O_2}=3.0,1.32=9,6(g)$
$\Rightarrow m_{hh}=7,1+9,6=16,7(g)$
a)
Gọi n Fe = 3a(mol) ; n Mg = 2a(mol)
Suy ra :
3a.56 + 2a.24 = 21,6
=> a = 0,1
Vậy : n Fe = 0,3 ; n Mg = 0,2(mol)
$3Fe + 2O_2 \xrightarrow{t^o} Fe_3O_4$
$2Mg + O_2 \xrightarrow{t^o} 2MgO$
n Fe3O4 = 1/3 n Fe = 0,1(mol) => m Fe3O4 = 0,1.232 = 23,2(gam)
n MgO = n Mg = 0,2(mol) => m MgO = 0,2.40 = 8(gam)
b)
n O2 = 2/3 n Fe + 1/2 n Mg = 0,3(mol)
V O2 = 0,3.22,4 = 6,72 lít
1, a, + 8.2=16 => CH4
+ 8,5 . 2 = 17 => NH3
+ 16 . 2 =32 => O2
+ 22 . 2 = 44 => CO2
b, + 0,138 . 29 \(\approx4\) => He
+ 1,172 . 29 \(\approx34\) => H2S
+ 2,448 . 29 \(\approx71\Rightarrow Cl_2\)
+ 0,965 . 29 \(\approx28\) => N
\(n_C = a(mol) ; n_S = b(mol)\\ \Rightarrow 12a + 32b = 5,6(1)\\ C + O_2 \xrightarrow{t^o} CO_2\\ S + O_2 \xrightarrow{t^o} SO_2\\ n_{O_2} = n_C + n_S = a + b = \dfrac{9,6}{32} = 0,3(2)\\ (1)(2)\Rightarrow a = 0,2 ; b = 0,1\\ \%m_C = \dfrac{0,2.12}{5,6}.100\% =42,86\%\\ \%m_S = 100\%-42,86\% = 57,14\%\)
\(n_{CO_2} = n_C = 0,2(mol)\\ n_{SO_2} = n_S = 0,1(mol)\\ \%V_{CO_2} = \dfrac{0,2}{0,2 + 0,1}.100\% = 66,67\%\\ \%V_{SO_2} = 100\%-66,67\% = 33,33\%\\ m_{hh\ sau\ pư} = m_C + m_S + m_{O_2} = 5,6 + 9,6 = 15,2(gam)\\ \%m_{CO_2} = \dfrac{0,2.44}{15,2}.100\% = 57,89\%\\ \%m_{SO_2} = 100\% -57,89\% = 42,11\%\)
\(n_{O_2}=\dfrac{89.6}{22.4}=4\left(mol\right)\)
\(n_{H_2O}=3a\left(mol\right)\)
\(n_{CO_2}=a\left(mol\right)\)
\(2H_2+O_2\underrightarrow{^{^{t^0}}}2H_2O\)
\(2CO+O_2\underrightarrow{^{^{t^0}}}2CO_2\)
\(n_{O_2}=1.5a+0.5a=4\left(mol\right)\)
\(\Leftrightarrow a=2\)
\(n_{H_2}=3\left(mol\right),n_{CO}=1\left(mol\right)\)
\(\%V_{H_2}=\dfrac{3}{4}\cdot100\%=75\%\)
\(\%V_{CO}=25\%\)
\(\%m_{H_2}=\dfrac{3\cdot2}{3\cdot2+1\cdot28}\cdot100\%=17.64\%\)
\(\%m_{CO}=100-17.64=82.36\%\)
Gọi \(\left\{{}\begin{matrix}n_{Cl_2}=a\left(mol\right)\\n_{O_2}=b\left(mol\right)\end{matrix}\right.\)
Theo đề bài, ta có:
\(\dfrac{71a+32b}{a+b}=14.4=56\left(g\text{/}mol\right)\)
\(\Leftrightarrow\dfrac{a}{b}=\dfrac{8}{5}\\ \Rightarrow\%V_{O_2}=\%n_{O_2}=\dfrac{5}{5+8}.100\%=38,46\%\)
a, Gọi: nS = 2x (mol) ⇒ nP = x (mol)
⇒ 2x.32 + 31x = 19 ⇒ x = 0,2 (mol)
⇒ nS = 2.0,2 = 0,4 (mol) ⇒ mS = 0,4.32 = 12,8 (g)
mP = 0,2.31 = 6,2 (g)
b, PT: \(S+O_2\underrightarrow{t^o}SO_2\)
\(4P+5O_2\underrightarrow{t^o}2P_2O_5\)
Theo PT: \(n_{O_2}=n_S+\dfrac{5}{4}n_P=0,65\left(mol\right)\)
\(\Rightarrow m_{O_2}=0,65.32=20,8\left(g\right)\)
\(V_{O_2}=0,65.22,4=14,56\left(l\right)\)
⇒ 2x.32 + 31x = 19 ⇒ x = 0,2 (mol)
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