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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)
\(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)
PTHH: Zn + 2HCl --> ZnCl2 + H2
0,2-->0,4----->0,2--->0,2
=> VH2 = 0,2.22,4 = 4,48 (l)
b) mHCl = 0,4.36,5 = 14,6 (g)
=> \(m_{dd.HCl}=\dfrac{14,6.100}{7,3}=200\left(g\right)\)
c)
mdd sau pư = 13 + 200 - 0,2.2 = 212,6 (g)
mZnCl2 = 0,2.136 = 27,2 (g)
=> \(C\%=\dfrac{27,2}{212,6}.100\%=12,8\%\)
\(n_{Al}=\dfrac{0,54}{27}=0,02\left(mol\right)\\ m_{H_2SO_4}=9,8\%.40=3,92\left(g\right)\\ n_{H_2SO_4}=\dfrac{3,92}{98}=0,04\left(mol\right)\)
PTHH: 2Al + 3H2SO4 ---> Al2(SO4)3 + 3H2
LTL: \(\dfrac{0,02}{2}< \dfrac{0,04}{3}\rightarrow\)H2SO4 dư
Theo pt: \(\left\{{}\begin{matrix}n_{H_2SO_4\left(pư\right)}=n_{H_2}=\dfrac{3}{2}n_{Al}=\dfrac{3}{2}.0,02=0,03\left(mol\right)\\n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{2}n_{Al}=\dfrac{1}{2}.0,02=0,01\left(mol\right)\end{matrix}\right.\)
\(\rightarrow V_{H_2}=0,03.22,4=0,672\left(l\right)\\ m_{dd}=0,54+40=40,54\left(g\right)\\ \rightarrow\left\{{}\begin{matrix}C\%_{Al_2\left(SO_4\right)_3}=\dfrac{342.0,01}{40,54}=8,43\%\\C\%_{H_2SO_4\left(dư\right)}=\dfrac{\left(0,04-0,03\right).98}{40,54}=2,41\%\end{matrix}\right.\)
a, \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
b, \(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)
Theo PT: \(n_{H_2}=n_{Zn}=0,2\left(mol\right)\Rightarrow V_{H_2}=0,2.22,4=4,48\left(l\right)\)
c, \(n_{ZnCl_2}=n_{Zn}=0,2\left(mol\right)\Rightarrow m_{ZnCl_2}=0,2.136=27,2\left(g\right)\)
d, \(n_{HCl}=2n_{Zn}=0,4\left(mol\right)\Rightarrow m_{HCl}=0,4.36,5=14,6\left(g\right)\)
\(\Rightarrow m_{ddHCl}=\dfrac{14,6}{7,3\%}=200\left(g\right)\)
⇒ m dd sau pư = 13 + 200 - 0,2.2 = 212,6 (g)
\(\Rightarrow C\%_{ZnCl_2}=\dfrac{27,2}{212,6}.100\%\approx12,79\%\)
a)
$2Al +3H_2SO_4 \to Al_2(SO_4)_3 + 3H_2$
b)
$n_{H_2} = n_{H_2SO_4} = \dfrac{300.9,8\%}{98} = 0,3(mol)$
$V_{H_2} = 0,3.22,4 = 6,72(lít)$
c)
$n_{Al_2(SO_4)_3} = \dfrac{1}{3}n_{H_2SO_4} = 0,1(mol)$
$m_{Al_2(SO_4)_3} = 0,1.342 = 34,2(gam)$
d)
$n_{Al} = \dfrac{2}{3}n_{H_2SO_4} = 0,2(mol)$
$m_{dd} = 0,2.27 + 300 - 0,3.2 = 304,8(gam)$
$C\%_{Al_2(SO_4)_3} = \dfrac{34,2}{304,8}.100\% = 11,22\%$
nH2SO4=0,3(mol)
PTHH: 2Al + 3 H2SO4 -> Al2(SO4)3 + 3 H2
a) 0,2_______0,3______0,1______0,3(mol)
b) V(H2,đktc)=0,3.22,4=6,72(l)
c) a=mAl=0,2.27=5,4(g)
=>a=5,4(g)
d) mAl2(SO4)3=342.0,1=34,2(g)
e) mddAl2(SO4)3= 5,4+ 300 - 0,3.2= 304,8(g)
=>C%ddAl2(SO4)3= (34,2/304,8).100=11,22%
nAl= 0,04(mol)
PTHH: 2 Al + 3 H2SO4 -> Al2(SO4)3 + 3 H2
0,04___________0,06___0,02_____0,06(mol)
a) V(H2, đktc)=0,06.22,4=1,344(l)
b) VddH2SO4= 0,06/2=0,03(l)=30(ml)
c) VddAl2(SO4)3=VddH2SO4=0,03(l)
=>CMddAl2(SO4)3=0,02/0,03=2/3(M)
\(n_{Al}=\dfrac{1.08}{27}=0.04\left(mol\right)\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
\(0.04......0.06.............0.02...........0.06\)
\(V_{H_2}=0.06\cdot22.4=1.344\left(l\right)\)
\(V_{dd_{H_2SO_4}}=\dfrac{0.06}{2}=0.03\left(l\right)\)
\(C_{M_{Al_2\left(SO_4\right)_3}}=\dfrac{0.02}{0.03}=\dfrac{2}{3}\left(M\right)\)
mH2SO4=9,8%.300=29,4(g)
=> nH2SO4=0,3(mol)
a) PTHH: 2Al +3 H2SO4 -> Al2(SO4)3 + 3 H2
0,2<-------------0,3----------->0,1------------->0,3(mol)
b) a=mAl=0,2.27=5,4(g)
c) V(H2,đktc)=0,3.22,4=6,72(l)
d) mAl2(SO4)3=0,1.342=34,2(g)
e) mddAl2(SO4)3=mAl+mddH2SO4- mH2= 5,4+300-0,3.2= 304,8(g)
=> C%ddAl2(SO4)3=(34,2/304,8).100=11,22%
a) 2Al+ 3H2SO4→ Al2(SO4)3+ 3H2
(mol) 0,2 0,3 0,1 0,3
b) m H2SO4= 300. 9,8%= 29,4(g)
n H2SO4= \(\dfrac{m}{M}=\dfrac{29,4}{98}=0,3\)(mol)
c) V H2= n.22,4= 0,3.22,4= 6,72(lít)
m H2= n.m= 0,3.2= 0,6(g)
d) m Al2(SO4)3= n.M= 0,1.342= 34,2(g)
e) mAl= n.M= 0,2.27= 5,4(g)
mddsau phản ứng= mAl+ mdd H2SO4- m H2
= 5,4+300-0,6= 304,8(g)
=> C%ddsau phản ứng= \(\dfrac{34,2}{304,8}.100\%=11,22\%\)
2Al + 3H2SO4 \(\rightarrow\) Al2(SO4)3 + 3H2\(\uparrow\)
a) m\(H_2SO_4\) = \(\frac{100.9,8}{100}=9,8\left(g\right)\)
=> n\(H_2SO_4\) = \(\frac{9,8}{98}=0,1\left(mol\right)\)
Theo PT: nAl = \(\frac{2}{3}n_{H_2SO_4}=\frac{2}{3}.0,1=0,067\left(mol\right)\)
=> mAl = 0,067.27 = 1,809(g) = a
Theo PT: n\(H_2\) = n\(H_2SO_4\) = 0,1 (mol)
=> m\(H_2\) = 0,1.2 =0,2 (g)
=> V\(H_2\) = 0,1.22,4 = 2,24 (l) = V
b) Theo PT: n\(Al_2\left(SO_4\right)_3\)= \(\frac{1}{3}n\)\(H_2SO_4\) = \(\frac{1}{3}.0,1=0,03\left(mol\right)\)
=> m\(Al_2\left(SO_4\right)_3\) = 342.0,03 = 10,26 (g)
=> mdd sau pứ = 1,809 + 100 - 0,2 = 101,609 (g)
=> C%\(Al_2\left(SO_4\right)_3\) = \(\frac{10,26}{101,609}.100\%=10,1\%\)