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a, \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
b, \(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)
\(m_{HCl}=100.14,6\%=14,6\left(g\right)\Rightarrow n_{HCl}=\dfrac{14,6}{36,5}=0,4\left(mol\right)\)
Xét tỉ lệ: \(\dfrac{0,1}{1}< \dfrac{0,4}{2}\), ta được HCl dư.
Theo PT: \(n_{H_2}=n_{Zn}=0,1\left(mol\right)\Rightarrow V_{H_2}=0,1.22,4=2,24\left(l\right)\)
b, Theo PT: \(\left\{{}\begin{matrix}n_{HCl\left(pư\right)}=2n_{Zn}=0,2\left(mol\right)\\n_{ZnCl_2}=n_{Zn}=0,1\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow n_{HCl\left(dư\right)}=0,4-0,2=0,2\left(mol\right)\)
Ta có: m dd sau pư = 6,5 + 100 - 0,1.2 = 106,3 (g)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{ZnCl_2}=\dfrac{0,1.136}{106,3}.100\%\approx12,79\%\\C\%_{HCl\left(dư\right)}=\dfrac{0,2.36,5}{106,3}.100\%\approx6,87\%\end{matrix}\right.\)
a, Zn + 2HCl ----> ZnCl2 + H2↑
b, nZn= 6,5:65= 0,1 mol; nHCl= (100*14,6%)/36,5 = 0,4 mol
Zn + 2HCl ----> ZnCl2 + H2↑
trc pư: 0,1 0,4 (mol)
pư: 0,1 0,2 (mol)
sau pư:0 0,2 0,1 0,1 (mol)
VH2(dktc)= 0,1*22,4= 2,24 (L)
c, mZnCl2= 0,1* 136= 13,6 g
mHCl= 0,2* 36,5= 7,3 g
mdd = 6,5 +100 - 0,1*2 =106,3 g
C%ZnCl2= 13,6/106,3* 100%= 12,8%
C%HCl= 7,3/106,3*100%=6,8%
\(n_{Zn}=\dfrac{6.5}{65}=0.1\left(mol\right)\)
\(n_{HCl}=\dfrac{100\cdot14.6\%}{36.5}=0.4\left(mol\right)\)
\(Zn+2HCl\rightarrow ZnCl_2+H_2\)
\(1........2\)
\(0.1......0.4\)
\(LTL:\dfrac{0.1}{1}< \dfrac{0.4}{2}\Rightarrow HCldư\)
\(V_{H_2}=0.1\cdot22.4=2.24\left(l\right)\)
\(m_{\text{dung dịch sau phản ứng}}=6.5+100-0.1\cdot2=106.3\left(g\right)\)
\(C\%ZnCl_2=\dfrac{0.1\cdot136}{106.3}\cdot100\%=12.79\%\)
\(C\%HCl\left(dư\right)=\dfrac{\left(0.4-0.2\right)\cdot36.5}{106.3}\cdot100\%=6.87\%\%\)
Sửa đề: 8,4 gam Fe
\(a,n_{Fe}=\dfrac{8,4}{56}=0,15\left(mol\right)\\ n_{HCl}=\dfrac{14,6.175}{36,5.100}=0,7\left(mol\right)\)
PTHH: \(Fe+2HCl\rightarrow FeCl_2+H_2\)
ban đầu 0,15 0,7
phản ứng 0,15 0,3
sau pư 0 0,4 0,15 0,15
\(V_{H_2}=0,15.22,4=3,36\left(l\right)\)
\(b,m_{dd}=8,4+175-0,15.2=183,1\left(g\right)\\ \rightarrow\left\{{}\begin{matrix}C\%_{FeCl_2}=\dfrac{0,15.127}{183,1}.100\%=10,4\%\\C\%_{HCl\left(dư\right)}=\dfrac{0,4.36,5}{183,1}.100\%=7,97\%\end{matrix}\right.\)
a)
\(n_{Fe}=\dfrac{16,8}{56}=0,3\left(mol\right)\)
\(m_{HCl}=\dfrac{175.14,6}{100}=25,55\left(g\right)\\ \rightarrow n_{HCl}=\dfrac{25,55}{35,5}=0,7\left(mol\right)\)
PTHH: \(Fe+2HCl\rightarrow FeCl_2+H_2\)
bđ 0,3 0,7
pư 0,3 0,6
spư 0 0,1 0,3 0,3
=> VH2 = 0,3.22,4 = 6,72 (l)
b)
mdd = 16,8 + 175 - 0,3.2 = 191,2 (g)
=> \(\left\{{}\begin{matrix}C\%_{FeCl_2}=\dfrac{0,3.127}{191,2}.100\%=19,93\%\\C\%_{HCl\left(dư\right)}=\dfrac{0,1.36,5}{191,2}.100\%=1,91\%\end{matrix}\right.\)
\(n_{Fe}=\dfrac{16,8}{56}=0,3\left(mol\right)\\ n_{HCl}=\dfrac{\dfrac{175.14,6}{100}}{36,5}=0,7\left(mol\right)\\ pthh:Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\)
\(LTL:\dfrac{0,3}{1}< \dfrac{0,7}{2}\)
\(n_{H_2}=n_{Fe}=0,3\left(mol\right)\\
V_{H_2}=0,3.22,4=6,72\left(l\right)\\
m_{\text{dd}}=16,8+175-\left(0,3.2\right)=191,2\left(g\right)\\
n_{FeCl_2}=n_{Fe}=0,3\left(mol\right)\\
C\%_{FeCl_2}=\dfrac{0,3.127}{191,2}.100\%=19,92\%\)
=> HCl dư
nZn = \(\dfrac{6,5}{65}=0,1\left(mol\right)\)
mHCl = \(\dfrac{14,6\times100}{100}=14,6\left(g\right)\)
=> nHCl = \(\dfrac{14,6}{36,5}=0,4\left(mol\right)\)
Pt: Zn + 2HCl --> ZnCl2 + H2
0,1 mol-> 0,2 mol->0,1 mol-> 0,1 mol
Xét tỉ lệ mol giữa Zn và HCl:
\(\dfrac{0,1}{1}< \dfrac{0,4}{2}\)
Vậy HCl dư
VH2 thoát ra = 0,1 . 22,4 = 2,24 (lít)
mZnCl2 = 0,1 . 136 = 13,6 (g)
mdd sau pứ = mZn + mdd HCl - mH2
...................= 6,5 + 100 - 0,1 . 2 = 106,3 (g)
C% dd ZnCl2 = \(\dfrac{13,6}{106,3}.100\%=12,8\%\)
C% dd HCl dư = \(\dfrac{\left(0,4-0,2\right).36,5}{106,3}.100\%=6,9\%\)
nZn=0,1 mol
Zn +2HCl=> ZnCl2+ H2
0,1 mol =>0,2 mol
=>mHCl=36,5.0,2=7,3g
=>m dd HCl=7,3/14,6%=50g
mdd sau pứ=6,5+50-0,1.2=56,3g
=>C% dd ZnCl2=(0,1.136)/56,3.100%=24,16%
a.b. Zn + 2HCl ---> ZnCl2 + H2 (1)
Theo pt: 65g 73g 136g 2g
Theo đề: 6,5g 7,3g 13,6g
=> mddHCl=\(\frac{7,3.100}{14,6}=50\left(g\right)\)
c. Từ pt (1), ta có: \(C_{\%}=\frac{13,6}{50+6,5}.100\%=24,1\%\)
Fe+H2SO4->FeSO4+H2
0,15---0,15-----0,15---0,15 mol
n Fe=8,4\56=0,15 mol
=>VH2=0,15.22,4=3,36l
=>m H2SO4=0,15.98=14,7g
=>C% H2SO4=14,7\245 .100=6%
=>m dd muối=8,4+245-0,15.2=253,1g
=>C% muối =0,15.152\253,1 .100=9%
a) PTHH: Zn + 2HCl -> ZnCl2 + H2
b) nZn=6,5:65=0,1(mol)
Theo pt ta có: nH2 =nZn=0,1(mol)
-> VH2=0,1.22,4=2,24(l)
a,Ta có pthh
Zn +2HCl \(\rightarrow\) ZnCl2 + H2
b, Theo đề bài ta có
nZn=\(\dfrac{6,5}{65}=0,1\left(mol\right)\)
mct=mHCl=\(\dfrac{m\text{dd}.C\%}{100\%}=\dfrac{100.14,6\%}{100\%}=14,6\left(g\right)\)
-> nHCl=\(\dfrac{14,6}{36,5}=0,4\left(mol\right)\)
Theo pthh
nZn=\(\dfrac{0,1}{1}mol< nHCl=\dfrac{0,4}{2}mol\)
-> Số mol của HCl dư ( tính theo số mol của Zn)
Theo pthh
nH2=nZn=0,1 mol
-> VH2\(_{\left(\text{đ}ktc\right)}=0,1.22,4=2,24\left(l\right)\)
c, Theo pthh
nZnCl2=nZn=0,1 mol
-> mct=mZnCl2=0,1 . 136=13,6 g
nHCl=2nZn=2.0,1=0,2 mol
-> mct=mHCl(d\(_{\text{ư}}\)) = (0,4-0,2).36,5=7,3 g
mddZnCl2=mZn + mddHCl - mH2 = 6,5 +100 -0,1.2=106,3 g
\(\Rightarrow\) Nồng độ % của các chất trong DD thu được sau phản ứng là :
C%\(_{ZnCl2}=\dfrac{mct}{m\text{dd}}.100\%=\dfrac{13,6}{106,3}.100\%\approx12,794\%\)
C%HCl\(_{\left(d\text{ư}\right)}=\dfrac{mct}{m\text{dd}}.100\%=\dfrac{7,3}{106,3}.100\%\approx6,87\%\)