[losingeyelashes]

Hii. First post! I attempted to do this and got all the answers that I needed, but I'm not sure if they are correct or not. I'll tell you what I did to get the answer and then we'll go from there.

Question:
A reaction mixture of 4.0 mL of 0.002 M SCN- and 5.0 mL of 0.002 M Fe3+ is diluted to 10.0 mL with deionized water to form the blood-red FeNCS2+ complex. The equilibrium molar concentration of the FeNCS2+ determined from a standardization curve is 1.5x10^-4 mol/L. Calculate, in sequence, each of the following quantities in the aqueous solution to determine the equilibrium constant for the reaction:

Fe3+(aq) + SCN-(aq) <--> FeNCS2+(aq)

A. Moles of FeNCS2+ that form in reaching equilibrium
B. Moles of Fe3+ that react to form the FeNCS2+ at equilibrium
C. moles of SCN- that react to form the FeNCS2+ at equilibrium
D. moles of Fe3+ initially placed in the reaction system
E. moles of SCN- initially placed in the reaction system
F. moles of Fe3+ that remain unreacted at the equilibrium (d - b)
G. moles of SCN- that remain unreacted at the equilibrium (e - c)
H. molar concentration of Fe3+ (unreacted) at equilibrium
I. molar concentration of SCN- (unreacted) at equilibrium
J. molar concentration of FeNCS2+ at equilibrium
K. Kc = [FeNCS2+]/[Fe3+][SCN-]

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Alright! My answer is in *asterisks*

A. The concentration at equilibrium is 1.5x10^-4, so in a 10 mL sample there are *1.5x10^-6*
B. I found the original number of moles of Fe3+ (4 x 0.002/1000) and got 8 x 10^-6, then took that and subtracted it from the moles of FeNCS2+ (1.5x10^-6) and got *6.5x10^-6*
C. I did the same thing as B, except the original number of moles is 1 x 10^-5 and subtracted it from A and got *8.5x10^-6*
D. To find the initial, I used the beginning of the ICE table. I said .001 L x .002 M x .005 L = *1 x 10^-8*
E. Did the same thing as D. I said .001 L x .002 M x .004 L and got *8 x 10^-9*
F. I subtracted part d from b. *-6.49x10^-6*
G. I subtracted part e from c. *-8.49x10^-6*
H. I found the molar concentration (M1V1=M2V2) and got *6.5x10^-4*
I. I found the molar concentration (M1V1=M2V2) and got *8.5x10^-4*
J. This was given.
K. I said 1.5x10^-4/(6.5x10^-4)(8.5x10^-4) and got *271.5*

Any help is so appreciated. Thank you.