Chemistry - balance equation

kazinvictus

2010-02-14 7:17 pm

Q1) Construct a balanced equation for the formation of sulfuric acid from oleum.

Q2) Given that H2C2O4-->Co2. Balance the equation and hence write a balanced equation for its reaction with permanganate ions.

Q3) Five moles of ferrous ions (Fe+) react qyantitatively with one mole of permanganate ions in acid solution. Write equations for the oxidation and reduction reactions and hence obtain a balanced equation for the overall reaction.

Q4) A student finds that 20.40mL of sodium hydroxide solution exactly neutralises 25.0mL of the acetic acid solution. Write an equation for the reaction that occurs and then calculate the concentration ( in mol L-1) of the acetic acid solution.

Thank you!

回答 (1)

六呎將軍

2010-02-14 7:56 pm

✔ 最佳答案

(1) H2S2O7 + H2O → 2H2SO4

(2) C2O42- → 2CO2 + 2e

Half equation of permanganate: MnO4- + 8H+ + 5e → Mn2+ + 4H2O

Overall equation: 5C2O42- + 2MnO4- + 16H+ → 10CO2 + 2Mn2+ + 8H2O

(3) Oxidation half: Fe2+ → Fe3+ + e

Reduction half: MnO4- + 8H+ + 5e → Mn2+ + 4H2O

Overall: 5Fe2+ + MnO4- + 8H+ → 5Fe3+ + Mn2+ + 4H2O

(4) NaOH + HAc → NaAc + H2O

Suppose that concentration of NaOH is x M, then:

No. of moles of NaOH = 0.0204x

No. of moles of HAc = 0.0204x

Conc. of HAc = 0.0204x/0.025 = 0.816x M

參考: Myself

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