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Urgent - Kimia (Butuh bantuan teman-teman secepatnya, Besok dikumpul)

Dimulai oleh IndahLestari, April 07, 2015, 04:37:39 PM

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Mohon bantuannya untuk PR Kimia (dalam bahasa inggris):

Bronze is an alloy of copper and tin. The problem is to find the ppercentage by mass of tin in the alloy. Potassium manganate (VII) oxidies tin (II) ions to tin (IV) ions.

A 9.40 g sample of powdered bronze was warmed with an excess of dilute sulphuric acid to convert the tin into tin (II) sulphate. After filtration, the solution was made up to 250 cm3.

In a titration, 25.0 cm3 of the solution of tin (II) sulphate required 19.0 cm3 of 0.0200 mol dm-3 potassium manganate (VII) solution for oxidation.

a. Why was the solution obtained from bronze filtered?
b. What conditions were employed for the titration?
c. How was the end-point of the titration spotted?
d. Write the half-equations for : (i) the oxidation of tin (II) to tin (IV), (ii) the reduction of manganate (VII) to manganate (II).
e. Combine the half-equations to give the equation for the reaction
f. Calculate the percentage by mass of tin in the alloy

Mohon bantuan teman-teman.. Terima kasih..  :)