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12 tháng 10 2016

a) nH2SO4 = 0,2 . 1 = 0,2 mol

H2SO4  +   2NaOH  -> Na2SO4  + 2H2O

0,2                0,4

mNaOH = 0,4 . 40 = 16g

mddNaOH = \(\frac{16.100\%}{20\%}=80g\)

b) 2KOH + H2SO4 -> K2SO4 + 2H2O

0,4 <---------- 0,2

=> mKOH = 0,4 . 56 = 22,4 g

mddKOH = \(\frac{22,4.100\%}{5,6\%}=400g\)

VddKOH = \(\frac{400}{1,045}=383ml\)

 

 

28 tháng 10 2021

Ta có: \(C_{\%_{H_2SO_4}}=\dfrac{m_{H_2SO_4}}{200}.100\%=14,7\%\)

=> \(m_{H_2SO_4}=29,4\left(g\right)\)

=> \(n_{H_2SO_4}=\dfrac{29,4}{98}=0,3\left(mol\right)\)

a. PTHH: 2KOH + H2SO4 ---> K2SO4 + 2H2O

Theo PT: \(n_{KOH}=2.n_{H_2SO_4}=2.0,3=0,6\left(mol\right)\)

=> \(m_{KOH}=0,6.56=33,6\left(g\right)\)

Ta có: \(C_{\%_{KOH}}=\dfrac{33,6}{m_{dd_{KOH}}}.100\%=5,6\%\)

=> \(m_{dd_{KOH}}=600\left(g\right)\)

Theo đề, ta có: 

\(D=\dfrac{600}{V_{dd_{KOH}}}=10,45\)(g/ml)

=> \(V_{dd_{KOH}}=57,42\left(ml\right)\)

b. Ta có: \(m_{dd_{K_2SO_4}}=200+33,6=233,6\left(g\right)\)

Theo PT: \(n_{K_2SO_4}=n_{H_2SO_4}=0,3\left(mol\right)\)

=> \(m_{K_2SO_4}=0,3.174=52,2\left(g\right)\)

=> \(C_{\%_{K_2SO_4}}=\dfrac{52,2}{233,6}.100\%=22,35\%\)

PTHH: \(H_2SO_4+2KOH\rightarrow K_2SO+2H_2O\)

Ta có: \(n_{H_2SO_4}=0,2\cdot1=0,2\left(mol\right)\)

\(\Rightarrow\left\{{}\begin{matrix}n_{KOH}=0,4\left(mol\right)\\n_{K_2SO_4}=0,2\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}V_{ddKOH}=\dfrac{\dfrac{0,4\cdot56}{6\%}}{1,048}\approx356,2\left(ml\right)\\C_{M_{K_2SO_4}}=\dfrac{0,2}{0,2+0,3562}\approx0,36\left(M\right)\end{matrix}\right.\)   

\(n_{H_2SO_4}=1.0,2=0,2\left(mol\right)\\ H_2SO_4+2KOH\rightarrow K_2SO_4+2H_2O\\ 0,2.........0,4........0,2.......0,2\left(mol\right)\\ a.m_{ddKOH}=\dfrac{0,4.56.100}{6}=\dfrac{1120}{3}\left(g\right)\\ V_{ddKOH}=\dfrac{\dfrac{1120}{3}}{1,048}=\dfrac{140000}{393}\left(ml\right)\approx0,356\left(l\right)\)

\(b.C_{MddK_2SO_4}=\dfrac{0,2}{\dfrac{140000}{393}+0,2}\approx0,00056\left(M\right)\)

Câu 16:

PTHH: \(KOH+HCl\rightarrow KCl+H_2O\)

Ta có: \(n_{HCl}=0,25\cdot1,5=0,375\left(mol\right)=n_{KOH}=n_{KCl}\)

\(\Rightarrow\left\{{}\begin{matrix}V_{KOH}=\dfrac{0,375}{2}=0,1875\left(l\right)\\C_{M_{KCl}}=\dfrac{0,375}{0,1875+0,25}\approx0,86\left(M\right)\end{matrix}\right.\)

Câu 18:

PTHH: \(2KOH+H_2SO_4\rightarrow K_2SO_4+2H_2O\)

a) Ta có: \(n_{H_2SO_4}=\dfrac{200\cdot14,7\%}{98}=0,3\left(mol\right)\)

\(\Rightarrow n_{KOH}=0,6\left(mol\right)\) \(\Rightarrow m_{ddKOH}=\dfrac{0,6\cdot56}{5,6\%}=600\left(g\right)\) \(\Rightarrow V_{ddKOH}=\dfrac{600}{10,45}\approx57,42\left(ml\right)\)

b) Theo PTHH: \(n_{K_2SO_4}=0,3\left(mol\right)\) \(\Rightarrow C\%_{K_2SO_4}=\dfrac{0,3\cdot174}{600+200}\cdot100\%=6,525\%\)

24 tháng 3 2017

a.250ml=0,25l ; nHCl=0,25.1,5=0,375mol

KOH+HCl->KCl+H2O

1mol 1mol 1mol

0,375 0,375 0,375

VKOh=0,375/2=0,1875l

b.CM KCL=0,375/0,25=1,5M

c.NaOH+HCL=NaCl+H2O

1mol 1mol

0,375 0,375

mdd NaOH=0,375.40.100/10=150g

26 tháng 10 2017

Sau rùi bạn ơi

17 tháng 12 2023

\(n_{H_2SO_4}=0,1.0,75=0,075mol\\ H_2SO_4+2KOH\rightarrow K_2SO_4+2H_2O\)

0,075           0,15               0,075          0,15

\(a)m_{K_2SO_4}=0,075.175=13,05mol\)

\(b)H_2SO_4+2NaOH\rightarrow Na_2SO_4+2H_2O\\ n_{NaOH}=0,075.2=0,15mol\\ m_{ddNaOH}=\dfrac{0,15.40}{15\%}\cdot100\%=40g\\ V_{ddNaOH}=\dfrac{40}{1,05}=38,1ml\)      

22 tháng 8 2019
https://i.imgur.com/NjAnV1z.jpg
21 tháng 8 2019

\(n_{H_2SO_4}=0,2.0,25=0,05 mol \)
a) \(H_2SO_4+2KOH \rightarrow K_2SO_4+2H_2O\)
Theo PTHH ta có: \(n_{KOH}=2n_{H_2SO_4}=0,05.2=0,1 mol\)
\(\rightarrow V_{dd KOH}=\frac{n}{C_M}=\frac{0,1}{0,5}=0,2 \left(l\right)=200\left(ml\right)\)
\(n_{K_2SO_4}=n_{H_2SO_4}=0,05\left(mol\right)\)
\(m_{dd sau}=250+200=450=0,45\left(l\right)\)
\(\rightarrow C_{M K_2SO_4}=\frac{0,05}{0,45}=\frac{1}{9}M\)
b)\(H_2SO_4+2NaOH\rightarrow Na_2SO_4+2H_2O\)
\(n_{NaOH}=2.n_{H_2SO_4}=0,1\left(mol\right)\rightarrow m_{NaOH}=0,1.40=4\left(g\right)\)
\(m_{dd NaOH}=\frac{4.100}{20}=20\left(g\right)\)
\(n_{Na_2SO_4}=0,05\left(mol\right)\rightarrow m_{Na_2SO_4}=0,05.142=7,1\left(g\right)\)
Do D=1ml/g -> mdd H2SO4=250(g)
\(C\%_{Na_2SO_4}=\frac{7,1}{250+20}.100=2,63\%\)

13 tháng 9 2016

mKOH=28(g)

nKOH=0.5(mol)

PTHH:2KOH+H2SO4->K2SO4+2H2O

a)Theo pthh:nH2SO4=1/2 nKOH->nH2SO4=0.25(mol)

mH2SO4=0.25*98=24.5(g)

C%ddH2SO4=24.5/100*100=24.5%

theo pthh:nK2SO4=nH2SO4->nK2SO4=0.25(mol)

mK2SO4=0.25*(39*2+96)=43.5(g)

c)mdd sau phản ứng:200+100=300(g)

d) C% muối=43.5:300*100=14.5%