Answer to Question #18128 in Other Chemistry for Ani
2) The sodium dichromate solution from Problem 1 was used to titrate a solution made by dissolving 3.500 g of a pure ferrous salt in sulfuric acid. The titration required 47.22 mL of the sodium dichromate solution. Calculate the percent by mass of iron in the pure salt. The net ionic equation here is the same as in Problem 1. You will not be able to write a balanced molecular equation for this because the anion in the ferrous salt was not specified in this problem.
Fe2+ - 1e- → Fe3+ reductant
Cr2O72+ + 14H+ + 6e- → 2Cr3+ + 7H2O oxidant
n(FeSO4) = 1.285 / 152 = 0.00845 mol
n(Na2Cr2O7) = 0.00140899122 mol
Cm(Na2Cr2O7) = 0.00140899122 / 0.03578 = 0.0339 M
2) n(Na2Cr2O7) = 0.04722 * 0.0339 = 0.0016 mol
n(FeSO4) = 0.0016 * 6 = 0.0096 mol
m(Fe) = M(Fe) / M(FeSO4) * m
m(Fe) = 56/152 * 3.5 = 1.288 g
%(Fe) = 1.288 / 3.5 * 100 % = 36.8 %
Need a fast expert's response?Submit order
and get a quick answer at the best price
for any assignment or question with DETAILED EXPLANATIONS!