Cho 4,8 gam Mg phản ứng với 109,5 gam dung dịch HCl 10%. Sau phản ứng tính:
a) Khối lượng chất dư
b) Thể tích H2 đkc thu được
c) Khối lượng muối
*ai giúp mình với, mình cần gấp*
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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: \(C\%\left(HCl\right)=\dfrac{0.4\cdot36.5}{100}=14.6\%\)
\(n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\)
PTHH :
\(Mg+H_2SO_4\rightarrow MgSO_4+H_2\uparrow\)
0,1 0,1 0,1 0,1
\(a,m_{MgSO_4}=0,1.120=12\left(g\right)\)
\(b,V_{H_2}=0,1.22,4=2,24\left(l\right)\)
\(c,m_{ddH_2SO_4}=\dfrac{0,1.98.100}{10}=98\left(g\right)\)
\(a.n_{Mg\left(OH\right)_2}=\dfrac{17,4}{58}=0,3\left(mol\right)\\ Mg\left(OH\right)_2+2HCl\rightarrow MgCl_2+2H_2O\\ n_{HCl}=2n_{Mg\left(OH\right)_2}=0,6\left(mol\right)\\ CM_{HCl}=\dfrac{0,6}{0,2}=3M\\b. n_{Mg\left(OH\right)_2}=n_{MgCl_2}=0,3\left(mol\right)\\ m_{MgCl_2}=0,3.85=25,5\left(g\right)\\c.CM_{MgCl_2}=\dfrac{0,3}{0,2}=1,5M \)
a, \(n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\)
\(m_{HCl}=36,5.15\%=5,475\left(g\right)\Rightarrow n_{HCl}=\dfrac{5,475}{36,5}=0,15\left(mol\right)\)
PT: \(Mg+2HCl\rightarrow MgCl_2+H_2\)
Xét tỉ lệ: \(\dfrac{0,1}{1}>\dfrac{0,15}{2}\), ta được Mg dư.
Theo PT: \(n_{H_2}=\dfrac{1}{2}n_{HCl}=0,075\left(mol\right)\Rightarrow V_{H_2}=0,075.22,4=1,68\left(l\right)\)
b, \(n_{Mg\left(pư\right)}=\dfrac{1}{2}n_{HCl}=0,075\left(mol\right)\Rightarrow n_{Mg\left(dư\right)}=0,1-0,075=0,025\left(mol\right)\)
\(\Rightarrow m_{Mg\left(dư\right)}=0,025.24=0,6\left(g\right)\)
c, - Cách 1:
\(n_{MgCl_2}=\dfrac{1}{2}n_{HCl}=0,075\left(mol\right)\Rightarrow m_{MgCl_2}=0,075.95=7,125\left(g\right)\)
- Cách 2:
Theo ĐLBT KL, có: mMg (pư) + mHCl = mMgCl2 + mH2
⇒ mMgCl2 = 2,4 - 0,6 + 5,475 - 0,075.2 = 7,125 (g)
\(n_{Zn}=\dfrac{m}{M}=\dfrac{3,25}{65}=0,05\left(mol\right)\)
\(PTHH:Zn+2HCl\rightarrow ZnCl_2+H_2\)
1 2 1 1
0,05 0,1 0,05 0,05
a) \(V_{H_2}=n.24,79=0,05.24,79=1,2395\left(l\right)\)
\(m_{ZnCl_2}=n.M=0,05.\left(65+35,5.2\right)=6,8\left(g\right)\)
b) \(PTHH:CuO+H_2\underrightarrow{t^o}Cu+H_2O\)
Ta cos tỉ lệ: \(\dfrac{0,1}{1}>\dfrac{0,05}{1}\Rightarrow\) CuO dư.
Theo ptr, ta có: \(n_{Cu}=n_{H_2}=0,05mol\\ \Rightarrow m_{Cu}=n.M=0,05.64=3,2\left(g\right).\)
a, PT: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
Ta có: \(n_{Zn}=\dfrac{3,25}{65}=0,05\left(mol\right)\)
THeo PT: \(n_{ZnCl_2}=n_{H_2}=n_{Zn}=0,05\left(mol\right)\)
\(\Rightarrow V_{H_2}=0,05.24,79=1,2395\left(l\right)\)
\(m_{ZnCl_2}=0,05.136=6,8\left(g\right)\)
b, Ta có: \(n_{CuO}=\dfrac{8}{80}=0,1\left(mol\right)\)
PT: \(CuO+H_2\underrightarrow{t^o}Cu+H_2O\)
Xét tỉ lệ: \(\dfrac{0,1}{1}>\dfrac{0,05}{1}\), ta được CuO dư.
Theo PT: \(n_{Cu}=n_{H_2}=0,05\left(mol\right)\Rightarrow m_{Cu}=0,05.64=3,2\left(g\right)\)
a/ \(n_{H_2}=\dfrac{7,437}{24,79}=0,3\left(mol\right)\)
PTHH: Mg + 2HCl → MgCl2 + H2
Mol: 0,3 0,6 0,3 0,3
\(m_{Mg}=0,3.24=7,2\left(g\right)\)
b/ \(m_{MgCl_2}=0,3.95=28,5\left(g\right)\)
c/ \(m_{HCl}=0,3.36,5=10,95\left(g\right)\)
Bài 11:
a) \(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)
\(n_{HCl}=\dfrac{10,95}{36,5}=0,3\left(mol\right)\)
PTHH: Zn + 2HCl --> ZnCl2 + H2
Xét tỉ lệ: \(\dfrac{0,2}{1}>\dfrac{0,3}{2}\) => Zn dư, HCl hết
PTHH: Zn + 2HCl --> ZnCl2 + H2
0,15<--0,3---------->0,15
=>mZn(dư) = (0,2-0,15).65 = 3,25 (g)
b) VH2 = 0,15.24,79 = 3,7185 (l)
\(n_{Al}=\dfrac{10.8}{27}=0.4\left(mol\right)\)
\(n_{H_2SO_4}=\dfrac{22.4}{98}=\dfrac{8}{35}\left(mol\right)\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
\(2............3\)
\(0.4..........\dfrac{8}{35}\)
\(LTL:\dfrac{0.4}{2}>\dfrac{\dfrac{8}{35}}{3}\Rightarrow Aldư\)
\(m_{Al\left(dư\right)}=\left(0.4-\dfrac{8}{35}\cdot\dfrac{2}{3}\right)\cdot27=6.68\left(g\right)\)
\(m_{Al_2\left(SO_4\right)_3}=\dfrac{8}{35\cdot3}\cdot342=26.05\left(g\right)\)
\(V_{H_2}=\dfrac{8}{35}\cdot22.4=5.12\left(l\right)\)
\(a,n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)\\ m_{HCl}=\dfrac{109,5\cdot10\%}{100\%}=10,95\left(g\right)\\ \Rightarrow n_{HCl}=\dfrac{10,95}{36,5}=0,3\left(mol\right)\\ PTHH:Mg+2HCl\rightarrow MgCl_2+H_2\\ \text{Vì }\dfrac{n_{HCl}}{2}< \dfrac{n_{Mg}}{1}\text{ nên sau p/ứ }Mg\text{ dư}\\ \Rightarrow n_{Mg}=\dfrac{1}{2}n_{HCl}=0,15\left(mol\right)\\ \Rightarrow n_{Mg\left(dư\right)}=0,2-0,15=0,05\left(mol\right)\\ \Rightarrow m_{Mg\left(dư\right)}=0,05\cdot24=1,2\left(g\right)\)
\(b,n_{H_2}=\dfrac{1}{2}n_{HCl}=0,15\left(mol\right)\\ \Rightarrow V_{H_2\left(đktc\right)}=0,15\cdot22,4=3,36\left(l\right)\\ c,n_{MgCl_2}=n_{H_2}=0,15\left(mol\right)\\ \Rightarrow m_{MgCl_2}=0,15\cdot95=14,25\left(g\right)\)