With the initial concentrations of [SCN]= 0.0005 M, [Fe3+]= 0.000698M, and [Fe(SCN)2+]=0.000M, determine the value of k if the [Fe(SCN)2+] at equilibrium is 0.0000866M.
Fe3+(aq) + SCN (aq) = Fe(SCN)2+ (aq)
..............Fe^3+ + SCN^-==>FeSCN^2+
initial.....0.0005...0.000698...0
change.........-x......-x.......+x
equil... 0.0005-x..0.000698-x...8.66E-5
so x must be 8.66E-5 which allows you to determine SCN^- and Fe(III) at equil then plug into the Kc expression to determine k.
210
To determine the value of k, you can use the equation for the equilibrium constant (Kc) for the reaction:
Kc = [Fe(SCN)2+]/([Fe3+][SCN-])
Given that the equilibrium concentration of [Fe(SCN)2+] is 0.0000866 M, and the initial concentrations of [Fe3+] and [SCN-] are 0.000698 M and 0.0005 M, respectively, you can substitute these values into the equation:
Kc = (0.0000866 M)/((0.000698 M)(0.0005 M))
Simplifying the expression:
Kc = 0.0000866 M / (0.000349 M^2)
Kc = 0.247 M^-2
Thus, the value of k for the reaction is approximately 0.247 M^-2.
To determine the value of k, we can use the equation for the equilibrium constant (Kc) for this reaction:
Kc = [Fe(SCN)2+] / ([Fe3+][SCN-])
Given the initial concentrations and the concentration of [Fe(SCN)2+] at equilibrium, we can plug these values into the equation and solve for k.
Given:
[SCN-] = 0.0005 M
[Fe3+] = 0.000698 M
[Fe(SCN)2+] at equilibrium = 0.0000866 M
Substituting these values into the equation:
Kc = 0.0000866 / (0.000698 * 0.0005)
Simplifying:
Kc = 0.0000866 / 0.000000349
Kc ≈ 247.850
Therefore, the value of k for this reaction is approximately 247.850.