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Help me please?? REDOX titration.. please? will appreciate it very much? please

Submitted by westley_31 on Sat, 08/28/2010 - 11:27

1. a 0.5000g sample of uranium alloy is dissolved in acid UC ₂²+. The uranium is passed through a lead reductor and reduced to uranium(IV). The reduced solution is titrated according to the reaction

2Ce+4 + U+4 + 2H20 --> UO₂+² + 2Ce+3 + 4H+

if 19.50ml of 0.1000 Normal cerium (IV) is required for the titration, what is the percentage of uranium in the alloy?

2. The iron in a 1.0000g rock sample is dissolved, reduced to Fe+2 and titrated with dichromate. If the titration requires 12.40ml of 0.5000 Normal dichromate, what is the percentage of Fe2O3 in the sample?

3. a 1.2500g sample of pure As2O3 is weighed into 250ml volumetric flask, solved and diluted to volume. A 25.00ml aliquot of this solution requires 26.00ml of iodine solution for titration to the starch end point. Calculate the percentage of As in 1.0000g ore sample that requires 15.00ml of this same solution for titration.

4. a 10.0ml portion of a solution containing I2 and KI requires .83ml of 0.120 Normal Na2S2O3 to titrate an end point with starch inidicator. Another 10.0ml portion, after acidification with concentrated HCl, requires 10.50ml of .0100M KIO3 to titrate to an end point with chloroform indicator. How many grams of I2 and KI are in the 10.0ml portion?

5. what is the milliequivalent weight of Mg in the determination of the element in the precipitation with 8-hydroxyquinolineand titrating with standard KBo2 + KBr the oxine is liberated from the precipitate of HCl?

6. If a precipitate of Hg2Cl2 requires a volume of KIO3 (0.100 Normal as an ordinary iodimetric standard for thiosulfate) for titration in 4 Normal HCl solution (CHCl3 indicator) that is equal to the volume of 0.1200 Molarity Na2S2O3 solution required to titrate the I2 liberated from 0.1392g of KBrO3 by excess KI in the presence of diluted acid, what weight of Hg is present in the Hg2Cl2 titrated?

can you please show your computations? thanks