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\(n_{Na}=\dfrac{4,6}{23}=0,2\left(mol\right)\)
PT: \(4Na+O_2\underrightarrow{t^o}2Na_2O\)
Theo PT: \(n_{Na_2O\left(LT\right)}=\dfrac{1}{2}n_{Na}=0,1\left(mol\right)\)
\(\Rightarrow m_{Na_2O\left(LT\right)}=0,1.62=6,2\left(g\right)\)
\(\Rightarrow H=\dfrac{4,96}{6,2}.100\%=80\%\)
Sửa đề: 7,43 (l) → 7,437 (l)
Ta có: \(n_{H_2}=\dfrac{7,437}{24,79}=0,3\left(mol\right)\)
PT: \(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
Theo PT: nHCl = 2nH2 = 0,6 (mol)
a, \(2Cu+O_2\underrightarrow{t^o}2CuO\)
\(2Mg+O_2\underrightarrow{t^o}2MgO\)
b, \(\dfrac{m_{CuO}}{m_{MgO}}=\dfrac{2}{1}\Rightarrow\dfrac{n_{CuO}}{n_{MgO}}=\dfrac{2}{1}:\dfrac{80}{40}=1\)
⇒ nCuO = nMgO (1)
Có: m chất rắn tăng = mO2 = 32 (g)
Theo PT: \(n_{O_2}=\dfrac{1}{2}n_{CuO}+\dfrac{1}{2}n_{MgO}=\dfrac{32}{32}=1\left(mol\right)\left(2\right)\)
Từ (1) và (2) ⇒ nCuO = nMgO = 1 (mol)
⇒ mCuO = 1.80 = 80 (g)
mMgO = 1.40 = 40 (g)
Ta có: m1 + m2 = 150 (1)
mNaNO3 (10%) = m1.10% (g)
mNaNO3 (2,5%) = m2.2,5% (g)
⇒ m1.10% + m2.2,5% = 150.5% (2)
Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}m_1=50\left(g\right)\\m_2=100\left(g\right)\end{matrix}\right.\)
a, \(Fe+2HCl\rightarrow FeCl_2+H_2\)
b, Ta có: \(n_{Fe}=\dfrac{5,6}{56}=0,1\left(mol\right)\)
Theo PT: \(n_{FeCl_2}=n_{H_2}=n_{Fe}=0,1\left(mol\right)\)
\(\Rightarrow V_{H_2}=0,1.24,79=2,479\left(l\right)\)
\(m_{FeCl_2}=0,1.127=12,7\left(g\right)\)
Ta có: m dd H2SO4 = 200.1,14 = 228 (g)
\(\Rightarrow m_{H_2SO_4}=228.9,8\%=22,344\left(g\right)\)
\(\Rightarrow n_{H_2SO_4}=\dfrac{22,344}{98}=0,228\left(mol\right)\)
PT: \(2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\)
a, Theo PT: \(n_{NaOH}=2n_{H_2SO_4}=0,456\left(mol\right)\)
\(\Rightarrow m_{ddNaOH}=\dfrac{0,456.40}{4\%}=456\left(g\right)\)
b, Theo PT: \(n_{Na_2SO_4}=n_{H_2SO_4}=0,228\left(mol\right)\)
\(\Rightarrow C\%_{Na_2SO_4}=\dfrac{0,228.142}{456+228}.100\%\approx4,73\%\)
Ta có: \(n_{Al}=\dfrac{m_{Al}}{M_{Al}}=\dfrac{2,7}{27}=0,1\left(mol\right)\)
PT: \(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
a, Theo PT: \(n_{H_2\left(LT\right)}=\dfrac{3}{2}n_{Al}=0,15\left(mol\right)\)
\(\Rightarrow V_{H_2\left(LT\right)}=0,15.24,79=3,7185\left(l\right)\)
\(\Rightarrow H=\dfrac{V_{H_2\left(TT\right)}}{V_{H_2\left(LT\right)}}.100\%=\dfrac{2,479}{3,7185}.100\%\approx66,67\%\)
b, \(n_{HCl}=\dfrac{6}{2}n_{Al}=0,3\left(mol\right)\)
\(\Rightarrow V_{HCl}=\dfrac{n_{HCl}}{C_{M_{HCl}}}=\dfrac{0,3}{1,5}=0,2\left(l\right)\)
c, \(n_{AlCl_3}=n_{Al}=0,1\left(mol\right)\)
\(\Rightarrow m_{AlCl_3}=n_{AlCl_3}.M_{AlCl_3}=0,1.133,5=13,35\left(g\right)\)
\(a.n_{H_2}=\dfrac{3,36}{22,4}=0,15mol\\ 2Al+6HCl\rightarrow2AlCl_3+3H_2\)
0,1 0,3 0,1 0,15
\(m_{Al}=0,1.27=2,7g\\ b.C_{M_{HCl}}=\dfrac{0,3}{0,3}=1M\\ c.C_{\%HCl}=\dfrac{0,3.36,5}{300.1,2}\cdot100=3,04\%\\ d)m_{dd}=2,7+300.1,2-0,15.2=362,4g\\ C_{\%AlCl_3}=\dfrac{0,1.133,5}{362,4}\cdot100=3,68\%\)
`#3107.101107`
`a)`
n của Fe trong phản ứng là:
\(\text{n}_{\text{Fe}}=\dfrac{\text{m}_{\text{Fe}}}{\text{M}_{\text{Fe}}}=\dfrac{5,6}{56}=0,1\left(\text{mol}\right)\)
PTHH: \(\text{Fe}+2\text{HCl}\rightarrow\text{FeCl}_2+\text{H}_2\)
Theo pt: `1` mol Fe phản ứng thu được `1` mol H2
`=>`\(\text{n}_{\text{H}_2}=0,1\text{ mol}\)
V của khí H2 sinh ra ở đktc là:
\(\text{V}_{\text{H}_2}=\text{n}_{\text{H}_2}\cdot22,4=0,1\cdot22,4=2,24\left(\text{l}\right)\)
`b)`
Theo pt: 1 : 2 : 1 \(\left(\text{mol}\right)\)
`=>`\(\text{n}_{\text{HCl}}=0,1\cdot2=0,2\left(\text{mol}\right)\) ; \(\text{n}_{\text{FeCl}_2}=0,1\text{ mol}\)
m của HCl đã phản ứng là:
\(\text{m}_{\text{HCl}}=\text{n}_{\text{ }\text{HCl}}\cdot\text{M}_{\text{HCl}}=0,2\cdot\left(1+35,5\right)=0,2\cdot36,5=7,3\left(\text{g}\right)\)
m của FeCl2 tạo thành là:
\(\text{m}_{\text{FeCl}_2}=\text{n}_{\text{FeCl}_2}\cdot\text{M}_{\text{FeCl}_2}=0,1\cdot\left(56+35,5\cdot2\right)=0,1\cdot127=12,7\left(\text{g}\right).\)