Question

Part II. Determination of Unknown SCN concentration. 0.387 9=3663.24-0.0427 1. Use the absorbance you measured for part II and the equation you obtained from part I to calculate the concentration of FeSCN In the cuvette. Show your calculations with formulas and report the result. 2. Since KSCR was limiting reactant, you may consider amounts of FeSCN and SCN to be the same. KSCN was diluted from the original unknown concentration in the bottle (c1) when the required by the protocol amount of it (V1) was diluted to the total amount of the prepared solution in part II (V2). The concentration of FeSCN you determined in part 11.1 is that final concentration of KSCN after the dilution, but before the reaction took place (c2). 3. Use C, V c, Vand rearrange it to find c1. Show your calculations, and report the result.

Answer 1

1) Since absorbance is 0.387 which is value of y. Put this value in equation y = 3663.2 x - 0.0427 and solve for x

0.387 = 3663.2 x - 0.0427

Add 0.0427 on both side,

0.387+0.0427 = 3663.2 x - 0.0427 + 0.0427

0.4297 = 3663.2 x

x = 0.4297/3663.2 = 1.1730 * 10-4 M

Therefore unknown concentration of FeSCN is 1.17 * 10-4 M.

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Thanks.