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Urgent- Kimia - PR - SMA Kelas X

Dimulai oleh IndahLestari, April 07, 2015, 09:29:49 PM

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Mohon bantuannya :
When potassium nitrate, KNO3, Iis heated, it decomposes according to the equation given below.
2KNO3 -> 2KNO2 + O2
a. Deduce the oxidation state of nitrogen in
(i) KNO3
(ii) KNO2

b. Calculate the maximum mass of KNO2 which could be obtained if 1.55 g KNO3 were fully decomposed by heat.

c. Another 1.55 g sample of KNO3, was partly decomposed by heating. The residue was dissolved in water and the volume of the solution made up to 25.0 cm3.
A 25.0 cm3portion of this solution was found to react in acid solution, with 28.9 cm3 of 0.0150 M KMnO4. The reaction can be represented by the equation:
2MnO4- + 5 NO2- + 6 H+ -> 2Mn2+ + 5NO3- + 3H2O

(i) Calculate the number of moles of KMnO4 which reacted with 25.0 cm3 of the solution

(ii) Calculate the total number of moles of KNO2 present in the residue

(iii) Calculate the mass of KNO2 present in the residue

(iv) Use the result obtained in part (b) and (c) (iii) to calculate the persentage conversion of KNO3 to KNO2 in the experiment

Terima kasih..  :)