For the reaction that occurs in the voltaic cell Fe( s )|Fe2+( a q )||Cr3+( a q

Question

For the reaction that occurs in the voltaic cell
Fe(s)|Fe2+(aq)||Cr3+(aq),Cr2+(aq)|Pt(s)

Part A

Determine the equation for the cell reaction.

Express your answer as a net ion equation. Identify all of the phases in your answer.

Part B

Determine Ecell.

Express your answer using two significant figures.

Part C

Determine ?G.

Express your answer using two significant figures.

Part D

Determine K.

Express your answer using two significant figures.

Part E

Determine whether the reaction goes substantially to completion when the reactants and products are initially in their standard states.

Explanation / Answer

part A

anode : oxidation

Fe(s)------------------------->Fe2+(aq) +2e-

cathode : reduction

2Cr3+(aq) +2e- --------------------------->2Cr2+(aq)|

Net ionic reaction : Fe(s)+ 2Cr3+(aq)--------------> Fe2+(aq) + 2Cr2+(aq)

part B : from electrochemical series E0Cr+3/Cr+2= -0.424 V    , E0Fe+2/Fe = -0.44 V

E0cell= E0cathode- E0anode

E0cell= E0Cr+3/Cr+2- E0Fe+2/Fe

          = -0.424 - (-0.44)

          = 0.016 V

part C

detla G0 = -nF Ecell0

                   = -2 x 96500 x 0.016

                 = - 3.09 kJ

part D

E0= RT/n F *log Kc

R= 8.314 J/kmol

F= 96500 C

T= 298K   

RT/F = 0.0591

E0= 0.0591/n *log K

0.016 = 0.0591/2 * log K

K= 3.5

part E

yes the reaction complete. because here Ecell positive and delta G negative so this reaction is spontaneous .

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