Question

Please answer all three as they are three parts to the same question

(1) Calculate the standard potential of the cell

Pt (s) | cysteine (aq) , cystine (aq) || H+ (aq) | O2 (g) | Pt (s)

(2) Calculate the standard Gibbs energy and Enthalpy of the cell reaction at 25oC.

(3) Estimate the value of the Gibbs energy of the cell reaction at 35oC.

Answer 1

as follows 1) The standard potential for cystine and hydrogen are Eaineeateine -0.22 V = E 0.816V H H,O Since, the reduction potential of cystine is lower than hydrogen, therefore, it will be treated as anode Calculating E as follows: EaEathode -Ede 0.816 V - (-0.22 V) anode 1.036V Therefore, the standard reduction potential is 1.036 V 2) The standard Gibbs energy can be calculated as follows: AG nFE cell cell =-2x96500x1.036 V -199.948kJ The enthalpy can be calculated using following formula AG AH TAS cell The value of AS can be calculated as follows dE AS nF dT