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Câu 3.
a, \(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)
PTHH: Zn + H2SO4 → ZnSO4 + H2
Mol: 0,1 0,1 0,1 0,1
b,\(V_{H_2}=0,1.22,4=2,24\left(l\right)\)
c,\(m_{ZnSO_4}=0,1.161=16,1\left(g\right)\)
\(m_{ddsaupư}=6,5+\dfrac{0,1.98.100}{25}-0,1.2=45,5\left(g\right)\)
\(\Rightarrow C\%_{ddZnSO_4}=\dfrac{16,1.100\%}{45,5}=35,4\%\)
Theo đề bài ta có : ⎧⎪ ⎪ ⎪⎨⎪ ⎪ ⎪⎩VddH2O4=601,2=50(ml)nNaOH=20.20100.40=0,1(mol){VddH2O4=601,2=50(ml)nNaOH=20.20100.40=0,1(mol)
nFe = 1,68/56 = 0,03 mol
a) Ta có PTHH :
2NaOH + H2SO4 -> Na2SO4 + 2H2O
0,1mol......0,05mol
=> CMH2SO4 = 0,05/0,05=1(M)
nH2 = \(\frac{1,68}{22,4}\) = 0,075 (mol)
Mg + 2HCl \(\rightarrow\) MgCl2 + H2\(\uparrow\) (1)
0,075 <--------0,075 <--0,075 (mol)
MgO + 2HCl \(\rightarrow\) MgCl2 + H2O (2)
%mMg= \(\frac{0,075.24}{5,8}\) . 100% = 31,03 %
%m MgO = 68,97%
nMgO = \(\frac{5,8-0,075.24}{40}\) = 0,1 (mol)
Theo pt(2) nMgCl2 = nMgO= 0,1 (mol)
mdd sau pư = 5,8 + 194,35 - 0,075.2 = 200 (g)
C%(MgCl2) = \(\frac{95\left(0,075+0,1\right)}{200}\) . 100% = 8,3125%
CH3COOH + Mg ---> CH3COOMg + 1/2H2
(mol) 0,026 0,026 0,013
a) nCH3COOMg = 2,13 : 83 = 0,026 mol
=> C\(_M\)CH3COOH = 0,026 : 0,02 = 1,3 M
b) V\(_{H2}\)= 0,013 . 22,4 = 0,2912(lit)
c) CH3COOH + NaOH ----> CH3COONa + H2O
a) H2SO4+BaCl2---->BaSO4+2HCl
b) n\(_{H2SO4}=\frac{200.9,8}{100.98}=0,2\left(mol\right)\)
n\(_{BaCl2}=\frac{800.6,5}{100.208}=0,25\left(mol\right)\)
=> BaCl2 dư
Theo pthh
n\(_{BaSO4}=n_{H2SO4}=0,2\left(mol\right)\)
m\(_{BaSO4}=0,2.233=46,6\left(g\right)\)
m ddsau pư=800+200-46,6=953,4(g)
Theo pthh
n\(_{BaCl2}=n_{H2SO4}=0,2\left(mol\right)\)
n BaCl2 dư=0,25-0,2=0,05(mol)
C% BaCl2=\(\frac{0,05.208}{953,4}.100\%=1,09\%\)
Theo pthh
n\(_{HCl}=2n_{H2SO4}=0,2\left(mol\right)\)
C% HCl=\(\frac{0,2.36,5}{953,4}.100\%=0,77\%\%\)
\(\text{h2so4 + bacl2 = baso4 + h2o}\)
Ta có :
\(\text{n h2so4 = 0,2 mol}\)
\(\text{n bacl2 = 0,25 mol }\)
theo pthh thì n h2so4 = n bacl2
\(\text{mà n bacl2 có > n h2so4}\)
--> h2so4 hết, còn bacl2 dư 0,05 mol
\(\text{m kết tủa = m baso4 = 0,2.233= 46,6g}\)
dd sau pứ là bacl2 dư 0,05mol
\(\text{m dd sau pứ = 200 + 800- 46,6 = 753,4g}\)
\(\text{--> C% Bacl2 = 0,05.208÷753,4.100%= 1,38%}\)
Ta có: \(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)
a. PTHH: Zn + H2SO4 ---> ZnSO4 + H2
b. Theo PT: \(n_{H_2}=n_{Zn}=0,1\left(mol\right)\)
=> \(V_{H_2}=0,1.22,4=2,24\left(lít\right)\)
c. Theo PT: \(n_{H_2SO_4}=n_{Zn}=0,1\left(mol\right)\)
=> \(m_{H_2SO_4}=0,1.98=9,8\left(g\right)\)
Ta có: \(C_{M_{H_2SO_4}}=\dfrac{9,8}{m_{dd_{H_2SO_4}}}.100\%=25\%\)
=> \(m_{dd_{H_2SO_4}}=39,2\left(g\right)\)
Ta có: \(m_{H_2}=0,1.2=0,2\left(g\right)\)
=> \(m_{dd_{ZnSO_4}}=6,5+39,2-0,2=45,5\left(g\right)\)
Theo PT: \(n_{ZnSO_4}=n_{Zn}=0,1\left(mol\right)\)
=> \(m_{ZnSO_4}=0,1.161=16,1\left(g\right)\)
=> \(C_{\%_{ZnSO_4}}=\dfrac{16,1}{45,5}.100\%=35,4\%\)