Use the mean value off Keq to calculate the SCN- concentration in a solution whose initial Fe3+ concentration was 4.00x10^-2 M (.04M) and initial SCN- concentration was 1.00x10^-3M (.001M). Is all the SCN- in the form of FeNCS2+?

Mean value = 237

Question

Use the mean value off Keq to calculate the SCN- concentration in a solution whose initial Fe3+ concentration was 4.00x10^-2 M (.04M) and initial SCN- concentration was 1.00x10^-3M (.001M). Is all the SCN- in the form of FeNCS2+?

Mean value = 237

anonymous · Answer

did the quadratic and my x values were
0.0458 & 1.0086

anonymous · Answer

How can i determine is all the "SCN- in the form of FeNCS2+" ??

anonymous · Answer

@Luigi0210 would you be able to help ? :)

aaronq · Answer

You had this?         $\sf 237=\dfrac{x}{[(0.001-x)*(0.04-x)]}$

i got different values for x

x=0.000902591890708, x=0.0443168173919924

So to choose from these you need to just use some common sense. Only of these values is possible because the other one exceeds the initial concentration of $SCN^-$.

anonymous · Answer

@aaronq Thank you! I did realize i made i mistake. easy fix :)