\(n_{K_2O}=\dfrac{23.5}{94}=0.25\left(mol\right)\)
\(K_2O+H_2O\rightarrow2KOH\)
\(0.25...................0.5\)
\(C_{M_{KOH}}=\dfrac{0.5}{0.5}=1\left(M\right)\)
\(2KOH+H_2SO_4\rightarrow K_2SO_4+H_2O\)
\(0.5............0.25............0.25\)
\(m_{dd_{H_2SO_4}}=\dfrac{0.25\cdot98}{20\%}=122.5\left(g\right)\)
\(V_{dd_{H_2SO_4}}=\dfrac{122.5}{1.14}=107.5\left(ml\right)=0.1075\left(l\right)\)
\(C_{M_{K_2SO_4}}=\dfrac{0.25}{0.1075+0.5}=0.4\left(M\right)\)
nK2O = 23,5 : 94 = 0,25 (mol)
Vdd = 500ml = 0,5l
PT K2O + H2O ==> 2KOH
TPT 1 1 2 (mol)
TĐB: 0,25 --> 0,5 (mol)
a) CM KOH = 0,5 : 0,5 = 1(M)
b) PT: H2SO4 + 2KOH ==> K2SO4 + 2H2O
TPT: 1 2 1 2 (mol)
a.
\(n_{K_2O}=\dfrac{m}{M}=\dfrac{23,5}{94}=0,25\left(mol\right)\\ PT:\\ K_2O+H_2O\rightarrow2KOH\)
Theo pt: \(n_{KOH}=2n_{K_2O}=0,5\left(mol\right)\)
\(\Rightarrow C_{M\left(KOH\right)}=\dfrac{n}{V}=\dfrac{0,5}{0,5}=1\left(M\right)\)
b.
\(PT:\\ 2KOH+H_2SO_4\rightarrow K_2SO_4+2H_2O\)(2)
Theo pt, \(n_{H_2SO_4}=\dfrac{1}{2}n_{KOH}=0,25\left(mol\right)\)
\(\Rightarrow V_{ddH_2SO_4}=\dfrac{m_{dd}}{D}=\dfrac{n.M:C\%}{D}=\dfrac{0,25.98:20\%}{1,14}=\)107,46(ml)
c.
dd spư có chất tan là K2SO4
Theo pt (2), \(n_{K_2SO_4}=\dfrac{1}{2}n_{KOH}=0,25\left(mol\right)\)
=> CM = \(\dfrac{n}{V}=\dfrac{0,25}{0,107}=2,336\left(M\right)\)