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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
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: \(n_{K_2SO_4}=0,3\left(mol\right)\) \(\Rightarrow C\%_{K_2SO_4}=\dfrac{0,3\cdot174}{600+200}\cdot100\%=6,525\%\)
\(n_{H_2SO_4}=0,1.0,75=0,075mol\\ H_2SO_4+2KOH\rightarrow K_2SO_4+2H_2O\)
0,075 0,15 0,075 0,15
\(a)m_{K_2SO_4}=0,075.175=13,05mol\)
\(b)H_2SO_4+2NaOH\rightarrow Na_2SO_4+2H_2O\\ n_{NaOH}=0,075.2=0,15mol\\ m_{ddNaOH}=\dfrac{0,15.40}{15\%}\cdot100\%=40g\\ V_{ddNaOH}=\dfrac{40}{1,05}=38,1ml\)
PTHH: \(KOH+HCl\rightarrow KCl+H_2O\) (1)
a) Ta có: \(n_{HCl}=0,25\cdot1,5=0,375\left(mol\right)\)
\(\Rightarrow n_{KOH}=0,375mol\) \(\Rightarrow V_{KOH}=\frac{0,375}{2}=0,1875\left(l\right)=187,5\left(ml\right)\)
b) Theo PTHH (1): \(n_{KCl}=n_{HCl}=0,375\left(mol\right)\)
\(\Rightarrow C_{M_{KCl}}=\frac{0,375}{0,4375}\approx0,86\left(M\right)\)
c) PTHH: \(NaOH+HCl\rightarrow NaCl+H_2O\) (2)
Theo PTHH (2): \(n_{NaOH}=n_{HCl}=0,375mol\)
\(\Rightarrow m_{NaOH}=0,375\cdot40=15\left(g\right)\) \(\Rightarrow m_{ddNaOH}=\frac{15}{10\%}=150\left(g\right)\)