A student mixes 5.00 mL 2.00 x 10 ^-3 MFe(NO ₃ ) ₃ in 1M HNO ₃ with 3.00 mL 2.00 x 10 ^-3 M KSCN and 2.00 mL of water. She finds that in the equilibrium mixture the concentration of FESN ²⁺ is 7.0 x 10 ^-5 M. Find Kc for the reaction

FE3 ⁺ (aq) + SCN ^- (aq) ⇌ Fe(SCN) ²⁺ (aq)

1. Find the number of moles Fe ³⁺ and SCN ^- initially present.

___________________ moles Fe ³⁺ : _______________ moles SCN ^-

2. How many moles of FeSCN ²⁺ are in the mixture at the equilibrium? What is the volume of the equilibrium mixture.

___________________ ml: _______________ moles FeSCN ²⁺

___________________ moles Fe ³⁺ : _______________ moles SCN ^-

How many moles Fe ³⁺ and SCN ^- are used up in making the FeSCN ²⁺ ?

3. How many moles of Fe ³⁺ and SCN ^- remain in the solution at equilibrium?

___________________ moles Fe ³⁺ : _______________ moles SCN ^-

4. What are the concentrations of Fe ³⁺ . SCN ^- . FeSCN2 ⁺ at equilibrium?

[Fe ³⁺ ] = ________________ M; [SCN ^- ] = ___________________ M; [FeSCN ²⁺ ] = _____________ M

5. What is the value of K _c for the reaction?

K _c = __________