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\(1,PTHH:4Al+3O_2\xrightarrow{t^o}2Al_2O_3\\ Al_2O_3+6HCl\to 2AlCl_3+3H_2\\ 2,n_{HCl}=\dfrac{240.7,3\%}{100\%.36,5}=0,48(mol)\\ \Rightarrow n_{Al_2O_3}=\dfrac{1}{6}n_{HCl}=0,08(mol)\\ \Rightarrow n_{Al}=2n_{Al_2O_3}=0,16(mol)\\ \Rightarrow m_{Al}=0,16.27=4,32(g)\\ n_{H_2}=\dfrac{1}{2}n_{HCl}=0,24(mol)\\ n_{AlCl_3}=\dfrac{1}{3}n_{HCl}=0,16(mol)\\ \Rightarrow C\%_{AlCl_3}=\dfrac{0,16.133,5}{0,08.102+240-0,24.2}.100\%=8,62\%\)
Bài 9 :
\(a) n_{Fe_2O_3} = \dfrac{3,2}{160}=0,02(mol)\\ Fe_2O_3 + 3H_2SO_4 \to Fe_2(SO_4)_3 + 3H_2O\\ n_{H_2SO_4} = 3n_{Fe_2O_3} = 0,06(mol)\\ m_{dd\ H_2SO_4} = \dfrac{0,06.98}{19,6\%} = 30(gam)\\ b) \text{Chất tan : } Fe_2(SO_4)_3\\ n_{Fe_2(SO_4)_3} = n_{Fe_2O_3} = 0,02(mol)\\ m_{Fe_2(SO_4)_3} = 0,02.400 =8(gam)\)
Bài 1:
PTHH: \(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)
Ta có: \(n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{HCl}=0,4\left(mol\right)\\n_{H_2}=0,2\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{ddHCl}=\dfrac{0,4\cdot36,5}{14,6\%}=100\left(g\right)\\V_{H_2}=0,2\cdot22,4=4,48\left(l\right)\end{matrix}\right.\)
Bài 2:
PTHH: \(2KOH+H_2SO_4\rightarrow K_2SO_4+2H_2O\)
Ta có: \(\left\{{}\begin{matrix}n_{KOH}=\dfrac{100\cdot11,2\%}{56}=0,2\left(mol\right)\\n_{H_2SO_4}=\dfrac{150\cdot9,8\%}{98}=0,15\left(mol\right)\end{matrix}\right.\)
Xét tỉ lệ: \(\dfrac{0,2}{2}< \dfrac{0,15}{1}\) \(\Rightarrow\) H2SO4 còn dư, KOH p/ứ hết
\(\Rightarrow\left\{{}\begin{matrix}n_{K_2SO_4}=0,1\left(mol\right)\\n_{H_2SO_4\left(dư\right)}=0,05\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{K_2SO_4}=0,1\cdot174=17,4\left(g\right)\\m_{H_2SO_4\left(dư\right)}=0,05\cdot98=4,9\left(g\right)\end{matrix}\right.\)
Mặt khác: \(m_{dd}=m_{ddKOH}+m_{ddH_2SO_4}=250\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{K_2SO_4}=\dfrac{17,4}{250}\cdot100\%=6,96\%\\C\%_{H_2SO_4\left(dư\right)}=\dfrac{4,9}{250}\cdot100\%=1,96\%\end{matrix}\right.\)
a, Ta có: \(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
PT: \(M+H_2SO_4\rightarrow MSO_4+H_2\)
Theo PT: \(n_M=n_{H_2}=0,2\left(mol\right)\)
\(\Rightarrow M_M=\dfrac{11,2}{0,2}=56\left(g/mol\right)\)
→ M là Fe.
b, Theo PT: \(n_{FeSO_4}=n_{H_2SO_4\left(pư\right)}=n_{H_2}=0,2\left(mol\right)\)
⇒ nH2SO4 dư = 0,5.1 - 0,2 = 0,3 (mol)
\(\Rightarrow\left\{{}\begin{matrix}C_{M_{H_2SO_4\left(dư\right)}}=\dfrac{0,3}{0,5}=0,6\left(M\right)\\C_{M_{FeSO_4}}=\dfrac{0,2}{0,5}=0,4\left(M\right)\end{matrix}\right.\)
c, Ta có: \(n_{FeSO_4.7H_2O}=n_{FeSO_4}=0,2\left(mol\right)\)
\(\Rightarrow m_{FeSO_4.7H_2O}=0,2.278=55,6\left(g\right)\)
nH2 = 1,344 : 22,4 = 0,06(mol)
pthh 2M+ 3H2SO4 ---> M2(SO4)3+ 3H2
0,04<-- 0,06---------------------------0,06(mol)
M M = 1,08 : 0,04 = 27 (g/mol )
=> M : Al
mH2SO4 = 0,06.98 =5,88 (g)
nH2 = 1,344/22,4 = 0,06 (mol)
PTHH:
2M + 3H2SO4 -> Al2(SO4)3 + 3H2
0,04 <--- 0,06 <--- 0,02 <--- 0,06
M(M) = 1,08/0,04 = 27 (g/mol(
=> M là Al
mH2SO4 = 0,06 . 98 = 5,88 (g)
\(m_{H_2SO_4}=\dfrac{200.9,8}{100}=19,6\left(g\right)=>n_{H_2SO_4}=\dfrac{19,6}{98}=0,2\left(mol\right)\)
PTHH: MO + H2SO4 --> MSO4 + H2O
____0,2<---0,2---------->0,2
=> \(M_{MO}=\dfrac{16}{0,2}=80\left(g/mol\right)\)
=> MM = 64 (g/mol)
=> M là Cu
\(C\%\left(CuSO_4\right)=\dfrac{0,2.160}{16+200}.100\%=14,815\%\)