This is the question from #1: The standard mixture you were given was prepared b
ID: 503867 • Letter: T
Question
This is the question from #1:
The standard mixture you were given was prepared by mixing 18.0 mL of 0.200 M Fe(NO3)3 with 2.0 mL of 0.00200 M KSCN. Assuming that all of the SCN- reacted in this mixture, what is the final concentration of FeSCN2+ in the mixture?
For that, I got 2*10^-4M as the answer.
I need help with the second problem:
Use the value from #1 and the absorbance of the solution (recall A = 2-log %T) to determine the [FeSCN2+] in the other solutions based on their absorbances. [hint: Beer's Law says that absorbance is directly proportional to concentration]
Absorbances are as follows:
a) 2.304
b) 2.684
c) 2.41
d) 2.383
e) 2.343
f) 2.381
Explanation / Answer
equations needed:
[SCN–]eq = [SCN–]i – [FeNCS2+]eq
[FeNCS2+]eq = (Aeq/Astd) * [FeNCS2+]std
let,
Aeq is given= 2.4
Astd is given= 2.68
[FeNCS2+]std = .0002
plug it in!
[FeNCS2+]eq = (2.4/2.68) * .0002 = 1*10^-3 M
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