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a, \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
\(n_{H_2}=\dfrac{0,896}{22,4}=0,04\left(mol\right)\)
Theo PT: \(n_{Zn}=n_{H_2}=0,04\left(mol\right)\Rightarrow m_1=m_{Zn}=0,04.65=2,6\left(g\right)\)
\(n_{HCl}=2n_{H_2}=0,08\left(mol\right)\Rightarrow m_{HCl}=0,08.36,5=2,92\left(g\right)\)
\(\Rightarrow m_2=m_{ddHCl}=\dfrac{2,92}{14,6\%}=20\left(g\right)\)
b, Ta có: m dd sau pư = mZn + m dd HCl - mH2 = 22,52 (g)
\(n_{ZnCl_2}=n_{H_2}=0,04\left(mol\right)\)
\(\Rightarrow C\%_{ZnCl_2}=\dfrac{0,04.136}{22,52}.100\%\approx24,16\%\)
Ta có: \(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)
PT: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
____0,2_____0,4_____0,2____0,2 (mol)
a, \(V_{H_2}=0,2.24,79=4,958\left(l\right)\)
b, mZnCl2 = 0,2.136 = 27,2 (g)
c, Đề cho VTT > VLT nên bạn xem lại đề nhé.
a) Ta có: \(n_{H_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\)
PTHH: Zn + 2HCl -> ZnCl2 + H2
=> \(n_{HCl}=2.0,4=0,8\left(mol\right)\\ n_{Zn}=n_{ZnCl_2}=n_{H_2}=0,4\left(mol\right)\)
=> \(m_1=m_{Zn}=0,4.65=26\left(g\right)\)
\(m_2=m_{ddHCl}=\dfrac{36,5.0,8.100}{14,6}=200\left(g\right)\)
b) Chất có trong dd sau khi phản ứng kthúc là ZnCl2
=> \(C\%_{ddZnCl_2}=\dfrac{0,4.136}{26+200-0,4.2}.100=\dfrac{54,4}{225,2}.100\approx24,156\%\)
\(Na+H_2O->NaOH+\dfrac{1}{2}H_2\\ a.n_{Na}=\dfrac{m_1}{23}\left(mol\right)\\ m_{ddsau}=\dfrac{m_1}{23}+m_2-\dfrac{m_1}{46}=\dfrac{m_1}{46}+m_2\left(g\right)\\ C\%_B=\dfrac{\dfrac{40}{23}m_1}{\dfrac{m_1}{46}+m_2}\cdot100\%.\\ b.C_M=\dfrac{10dC\%}{M}=10\cdot1,2\cdot\dfrac{0,05}{40}=0,015\left(M\right)\)
\(Na+H_2O->NaOH+\dfrac{1}{2}H_2\\ a.n_{Na}=\dfrac{m_1}{23}\left(mol\right)\\ m_{ddsau}=m_1+m_2-\dfrac{m_1}{23}=\dfrac{22}{23}m_1+m_2\left(g\right)\\ C\%_B=\dfrac{\dfrac{40}{23}m_1}{\dfrac{22}{23}m_1+m_2}\cdot100\%.\\ b.C_M=\dfrac{10dC\%}{M}=10\cdot1,2\cdot\dfrac{0,05}{40}=0,015\left(M\right)\)
a,\(n_{Fe}=\dfrac{28}{56}=0,5\left(mol\right)\)
PTHH: Fe + 2HCl → FeCl2 + H2
Mol: 0,5 1 0,5 0,5
\(V_{ddHCl}=\dfrac{1}{2}=0,5\left(l\right)\)
b,\(V_{H_2}=0,5.22,4=11,2\left(l\right)\)
c,\(C_{M_{ddFeCl_2}}=\dfrac{0,5}{0,5}=1M\)
Ta có: \(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)
PT: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
a, nH2 = nZn = 0,2 (mol)
⇒ VH2 = 0,2.24,79 = 4,958 (l)
b, nZnCl2 = nZn = 0,2 (mol)
⇒ mZnCl2 = 0,2.136 = 27,2 (g)
c, \(H=\dfrac{3,225}{4,958}.100\%\approx65,05\%\)
Kẽm không phải kem nha bạn
Ta có nH2 = \(\dfrac{0,986}{22,4}\) = 0,44 ( mol )
Zn + 2HCl \(\rightarrow\) ZnCl2 + H2
0,44...0,88........0,44.....0,44
=> mZn = 65 . 0,44 = 28,6 ( gam )
=> mHCl = 36,5 . 0,88 = 32,12 ( gam )
=> mZnCl2 = 136 . 0,44 = 59,84 ( gam )
thả 78 gam K vào bình đựng 923 gam nước .C% của dd thu đc là ?