Đề: Cho 4,8 gam Mg tác dụng vừa đủ với 100 gam dung dịch HCl. Tính:
a) Thể tích khí thoát ra
b) Khối lượng muối thu được
c) Nồng độ phần trăm của dung dịch HCL
Nhờ các chiến thần hóa học giải giúp mình với ạ
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\(a.n_{Mg\left(OH\right)_2}=\dfrac{17,4}{58}=0,3\left(mol\right)\\ Mg\left(OH\right)_2+2HCl\rightarrow MgCl_2+2H_2O\\ n_{HCl}=2n_{Mg\left(OH\right)_2}=0,6\left(mol\right)\\ CM_{HCl}=\dfrac{0,6}{0,2}=3M\\b. n_{Mg\left(OH\right)_2}=n_{MgCl_2}=0,3\left(mol\right)\\ m_{MgCl_2}=0,3.85=25,5\left(g\right)\\c.CM_{MgCl_2}=\dfrac{0,3}{0,2}=1,5M \)
\(a,n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)\\ m_{HCl}=\dfrac{109,5\cdot10\%}{100\%}=10,95\left(g\right)\\ \Rightarrow n_{HCl}=\dfrac{10,95}{36,5}=0,3\left(mol\right)\\ PTHH:Mg+2HCl\rightarrow MgCl_2+H_2\\ \text{Vì }\dfrac{n_{HCl}}{2}< \dfrac{n_{Mg}}{1}\text{ nên sau p/ứ }Mg\text{ dư}\\ \Rightarrow n_{Mg}=\dfrac{1}{2}n_{HCl}=0,15\left(mol\right)\\ \Rightarrow n_{Mg\left(dư\right)}=0,2-0,15=0,05\left(mol\right)\\ \Rightarrow m_{Mg\left(dư\right)}=0,05\cdot24=1,2\left(g\right)\)
\(b,n_{H_2}=\dfrac{1}{2}n_{HCl}=0,15\left(mol\right)\\ \Rightarrow V_{H_2\left(đktc\right)}=0,15\cdot22,4=3,36\left(l\right)\\ c,n_{MgCl_2}=n_{H_2}=0,15\left(mol\right)\\ \Rightarrow m_{MgCl_2}=0,15\cdot95=14,25\left(g\right)\)
`a)PTHH:`
`Zn + 2HCl -> ZnCl_2 + H_2`
`0,2` `0,4` `0,2` `0,2` `(mol)`
`n_[Zn]=13/65=0,2(mol)`
`b)V_[H_2]=0,2.22,4=4,48(l)`
`c)m_[dd HCl]=[0,4.36,5]/5 . 100=292(g)`
`=>C%_[ZnCl_2]=[0,2.136]/[13+292-0,2.2].100~~8,93%`
\(n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)\\ Mg+2HCl\rightarrow MgCl_2+H_2\\ 0,2..............0,4.............0,2...............0,2\left(mol\right)\\ a,V_{H_2\left(đktc\right)}=0,2.22,4=4,48\left(l\right)\\ b,m_{MgCl_2}=95.0,2=19\left(g\right)\\ c,a=C_{MddHCl}=\dfrac{0,4}{0,2}=2\left(M\right)\)
\(n_{Zn}=\dfrac{13}{65}=0,2(mol)\\ a,PTHH:Zn+2HCl\to ZnCl_2+H_2\\ b,n_{HCl}=0,4(mol)\\ \Rightarrow C\%_{HCl}=\dfrac{0,4.36,5}{100}.100\%=14,6\%\\ c,n_{ZnCl_2}=n_{H_2}=0,2(mol)\\ \Rightarrow m_{ZnCl_2}=0,2.136=27,2(g)\\ \Rightarrow C\%_{ZnCl_2}=\dfrac{27,2}{13+100-0,2.2}.100\%\approx 24,16\%\)
a, \(Na_2CO_3+2HCl\rightarrow2NaCl+CO_2+H_2O\)
b, \(n_{CO_2}=\dfrac{0,896}{22,4}=0,04\left(mol\right)\)
Theo PT: \(n_{HCl}=2n_{CO_2}=0,08\left(mol\right)\)
\(\Rightarrow C_{M_{HCl}}=\dfrac{0,08}{0,2}=0,4\left(M\right)\)
c, \(n_{Na_2CO_3}=0,04\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{Na_2CO_3}=\dfrac{0,04.106}{10}.100\%=42,4\%\\\%m_{NaCl}=57,6\%\end{matrix}\right.\)
nAl = 5.4 / 27 = 0.2 (mol)
2Al + 6HCl => 2AlCl3 + 3H2
0.2......0.6............0.2.......0.3
a) VH2 = 0.3 * 22.4 = 6.72 (l)
b) mAlCl3 = 0.2 * 133.5 = 26.7 (g)
c) VddHCl = 0.6 / 1.5 = 0.4 (l)
d) CMAlCl3 = 0.2 / 0.4 = 0.5 (M)
PTHH: \(2Al+6HCl\rightarrow2AlCl_3+3H_2\uparrow\)
Ta có: \(n_{Al}=\dfrac{5,4}{27}=0,2\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{HCl}=0,6\left(mol\right)\\n_{AlCl_3}=0,2\left(mol\right)\\n_{H_2}=0,3\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}V_{H_2}=0,3\cdot22,4=6,72\left(l\right)\\m_{AlCl_3}=0,2\cdot133,5=26,7\left(g\right)\\V_{HCl}=\dfrac{0,6}{1,5}=0,4\left(l\right)=400\left(ml\right)\\C_{M_{AlCl_3}}=\dfrac{0,2}{0,4}=0,5\left(M\right)\end{matrix}\right.\)
a) Pt: \(Fe+2HCl\rightarrow FeCl_2+H_2\)
b) nFe = \(\dfrac{11,2}{56}=0,2mol\)
Theo pt: nH2 = nFe = 0,2 mol
=> VH2 = 0,2.22,4 = 4,48lit
c) Theo pt: nHCl = 2nFe = 0,4 mol
=> mHCl = 0,4.36,5 = 14,6 g
=> C% = \(\dfrac{14,6}{73}.100\%=20\%\)
a: \(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)
0,2 0,4 0,2 0,2
\(n_{Mg}=\dfrac{4.8}{24}=0.2\left(mol\right)\)
=>\(n_{H_2}=0.2\left(mol\right)\)
\(V_{H_2}=0.2\cdot22.4=4.48\left(lít\right)\)
b:
\(n_{MgCl_2}=n_{Mg}=0.2\left(mol\right)\)
\(m_{MgCl_2}=0.2\left(24+35.5\cdot2\right)=19\left(g\right)\)
c: \(C\%\left(HCl\right)=\dfrac{0.4\cdot36.5}{100}=14.6\%\)