Koliko treba uzeti cm3 rastvora CH3COOH koncentracije 1mol/dm3 i rastvora NaOH koncentracije 0.5 mol/dm3 da bi se dobilo 600 cm3 pufera koncentracije pH=4.44?
V=600 cm3 a pH=4.44
CH3COOH+NaOH-------------->CH3COONa+H2O
{H+}=10(na -pH)=10(na -4.44)=3.63*10(-5)
CH3COOH-------------->CH3COO- + H+
CH3COONa------------->CH3COO- + Na+
{CH3COO-}={NaOH}=0.5 mol/l
Ka={CH3COO-}*{H+}/{CH3COOH}
Ka={H+}*n{CH3COO-}/n{CH3COOH}
V1+V2=600 cm3 Ka=1.8*10(-5)
n{CH3COO-}/n{CH3COOH}=Ka/{H+}=1.8*10(-5)/3.63*10(-5)
n{CH3COO-}/n{CH3COOH}=0.5
c1*V1/c2*V2=0.5
0.5*V1/1*V2=0.5
0.5*V1=0.5*V2
V1=V2 pa su zapremine V1=300 cm3 CH3COOH a V2=300 cm3 NaOH
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V=600 cm3 a pH=4.44
CH3COOH+NaOH-------------->CH3COONa+H2O
{H+}=10(na -pH)=10(na -4.44)=3.63*10(-5)
CH3COOH-------------->CH3COO- + H+
CH3COONa------------->CH3COO- + Na+
{CH3COO-}={NaOH}=0.5 mol/l
Ka={CH3COO-}*{H+}/{CH3COOH}
Ka={H+}*n{CH3COO-}/n{CH3COOH}
V1+V2=600 cm3 Ka=1.8*10(-5)
n{CH3COO-}/n{CH3COOH}=Ka/{H+}=1.8*10(-5)/3.63*10(-5)
n{CH3COO-}/n{CH3COOH}=0.5
c1*V1/c2*V2=0.5
0.5*V1/1*V2=0.5
0.5*V1=0.5*V2
V1=V2 pa su zapremine V1=300 cm3 CH3COOH a V2=300 cm3 NaOH