Chemical Forums

Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: brooke627 on March 22, 2018, 09:12:16 PM

Title: Equilibrium constant for formation of FeSCN
Post by: brooke627 on March 22, 2018, 09:12:16 PM
Assume that Beer s Law plot prepared by a student exhibited a slope of 1.88 x 10^3 Abs M^-1. The student then prepared an equilibrium mixture having initial concentration of Fe3+ and SCN- ions of 1.0 x 10^-3 M each. After performing a blank correction she observed an absorbance of 0.28 for the equilibrium mixture.
a. Estimate the equlibrium concentration of the FeSCN2+ ion in this equilibrium mixture.
b. Calculate the Keq value for this mixture.

I got keq = -47/25000, but I have no idea if that's correct. I really don't even know where to start on the equilibrium concentration. I thought it was the same as calculating kc.
Title: Re: Equilibrium constant for formation of FeSCN
Post by: billnotgatez on March 22, 2018, 10:21:55 PM
You have to show your attempts or thoughts at solving the question to receive help.
This is a forum policy.
Click on the link near the top center of the forum page.
Forum Rules: Read This Before Posting.
http://www.chemicalforums.com/index.php?topic=65859.0 (http://www.chemicalforums.com/index.php?topic=65859.0)
Title: Re: Equilibrium constant for formation of FeSCN
Post by: Borek on March 23, 2018, 04:00:31 AM
This is about using Beer-Lambert law - you are given information, that allows you to calculate FeSCN2- concentration from the results of measurement. Have you tried that?