Question

PART 24) What are the units for Equilibrium Constant? A, Ms-s B) M C)Ms! D) si E) none of these. Please show your work for the following Question to get the full credit 25) Use the dilution formula to calculate the concentrations of irom(ll) ions and SCN ions when 5.00 ml of o.002M iron/(lI) nitrate is mixed with 4.00 mL of 0.002 M NaSCN and dilute nitric acid is added to bring the total volume of the solution to 20.0 ml M Fe below as the initial concentrations of the reactants. When these reactants come to equilibrium, the concentration of FesCN in the mxture is 1.5 x 10 M With that information, complete the M SCN Put these calculated values into the table equilibrium table FeSCNFeSCN Initial Change _ Equilibrium And calculate the equilibrium constant using the equilibrium concentrations calculated in the table above.

Answer 1

25) total Volume of solution = 20 mL

Initial Molarity of Fe³⁺ = 0.002 M

[M Fe³⁺]_ini = Initial Volume * Initial molarity / Final molarity = 5.00 mL * 0.002 M / 20 mL = 0.0005 M

Similarly, [M SCN^-]_ini = 0.002 M * 4 mL / 20 mL = 0.0004 M

	Fe3+	SCN-	<=>	FeSCN2+
I(M)	0.0005	0.0004		0
C(M)	-1.5 *10-4 = -0.00015	-0.00015		0.00015
E(M)	0.0005 - 0.00015 = 0.00035	0.00025		0.00015

K_a = [FeSCN²⁺] / [Fe³⁺][SCN^-] = (0.00015) / (0.00025)(0.00035) = 1.71 *10³