Question

Trung hòa 200ml dd H2SO4 1M bằng dd NaOH 20%

a. Tính khối lượng dd NaOH cần dùng

b. Nếu trung hòa dd H2SO4 trên bằng dd KOH 5.6% ( D= 1.045g/ml) thì cần bao nhiêu ml dung dịch KOH

Answer 1

nH2SO4=0,02.1=0,02(mol)nH2SO4=0,02.1=0,02(mol)

PTHH: H2SO4+2NaOH→Na2SO4+2H2OH2SO4+2NaOH→Na2SO4+2H2O

pư..............0,02..........0,04..............0,02...........0,04 (mol)

⇒mNaOH=0,04.40=1,6(g)⇒mNaOH=0,04.40=1,6(g)

⇒mddNaOH(20%)=1,620%=8(g)⇒mddNaOH(20%)=1,620%=8(g)

PTHH: H2SO4+2KOH→K2SO4+2H2OH2SO4+2KOH→K2SO4+2H2O

pư............0,02............0,04............0,02..........0,04 (mol)

⇒mKOH=0,04.56=2,24(g)⇒mKOH=0,04.56=2,24(g)

⇒mddKOH(5,6%)=2,245,6%=40(g)⇒mddKOH(5,6%)=2,245,6%=40(g)

⇒VKOH=401,045≈38,28(ml)

Answer 2

H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O (1)

\(n_{H_2SO_4}=0,2\times1=0,2\left(mol\right)\)

a) Theo PT1: \(n_{NaOH}=2n_{H_2SO_4}=2\times0,2=0,4\left(mol\right)\)

\(\Rightarrow m_{NaOH}=0,4\times40=16\left(g\right)\)

\(\Rightarrow m_{ddNaOH}=\frac{16}{20\%}=80\left(g\right)\)

b) H₂SO₄ + 2KOH → K₂SO₄ + 2H₂O (2)

Theo PT2: \(n_{KOH}=2n_{H_2SO_4}=2\times0,2=0,4\left(mol\right)\)

\(\Rightarrow m_{KOH}=0,4\times56=22,4\left(g\right)\)

\(\Rightarrow m_{ddKOH}=\frac{22,4}{5,6\%}=400\left(g\right)\)

\(\Rightarrow V_{ddKOH}=\frac{400}{1,045}=382,78\left(ml\right)\)

Answer 3

https://i.imgur.com/JIHvFYJ.jpg