Calculate Gibbs Free Energy. Please help me out? So hard. ?

Question

Ti(IV) ions and iron react according to the following reaction.

Sn4+ + Fe --> Fe2+ + Sn2+

A. Calculate the Gibbs free energy change for the reaction.

B. Determine the equilibrium constant, Keq, for the reaction at 25 degrees C.

Answer 1

You should have a table of standard Gibbs energies for reactions that, when added, yield that chemical reaction.  Or you have tables of standard enthalpies and entropies for reactions that you can use the formula G=H-TS to solve for the Gibbs energy.

Once you get the Gibbs energy, the formula for the Keq is G=-RTln(Keq).

Good luck!

Answer 2

Cathode reduction takes place

Anode oxidation takes place

E(standard electrode potential)[Sn4+ to Sn 2+] or E[cathode]=0.13volt

E(standard electrode potential)[Fe2+ to Fe ] or E[anode]= -0.44volt

E(standard cell potential)=E[cathode] - E[anode]

                                    =0.13-(-0.44)

                                    =0.57 V

n - number of electrons

F - faraday constant

G= -nFE(standard cell potential)

  = -2*96487*.57

  = -109995.18 J

G= -2.303RTlog K

R=8.314 J mol^-1 K^-1

T=25+273=298 K

after substituting value

K=1.89*10^19