One of the standard solutions had an abnormally low absorbance reading, causing

Question

One of the standard solutions had an abnormally low absorbance reading, causing a less positive slope for the data plot. Will the equilibrium concentrations of FeSCN^1-in the unknown solution be too high or too low? Explain. Will the calculated K for the equilibrium be too high, too low, or unaffected by the erred data plot? Explain. A mixture is prepared by combining 3.0 mL of 0.0050 M NaSCN solution with 4.0 mL of 0.0030 M Fe(NO_3)_3 solution, and 3.0 mL of 0.10 M HNO_3 solutions. Based on your K_eq value, determine the equilibrium concentrations of Fe^3+, SCN^-, and FeSCN^2+ in the solution.

Explanation / Answer

What is the calculated Kc? you are not putting that value or data to calculate that. However, I can give you some guidance to do this.

First, calculate innitial concentration of the reactants:
[Fe3+] = 0.0030 * (4/10) = 0.0012 M
[SCN-] = 0.0030 * (3/10) = 0.0009 M

Next, write the overall reaction and do an ICE chart:
r: Fe3+ + SCN- <---------> Fe(SCN)2+
i: 0.0012 0.0009 0
e: 0.0012-x 0.0009-x x

Finally, write the Kc expression, as you did in part b of question 1, and replace the values:
Kc = x / (0.0012-x)(0.0009-x)

With your calculated value of Kc, replace it here, and solve for x so you can know the equilibrium concentrations.

Hope this helps

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