# chemistry

posted by .

Construct a galvanic (voltaic) cell from the half reactions shown below.
Au3+ + 3 e- → Au (s) ξo= 1.420 V
Br2 (l) + 2 e-→ 2 Br- (aq) ξo= 1.087 V
Calculate the equilibrium constant (K) for this cell. Assume that the temperature is 298K.
First, consider what happens to the Nernst equation when the system reaches equilibrium:
ξ = ξo - (RT/nF) ln Q
What is ξ when the system has reached equilibrium? Is there any driving force left?
Remember that ∆G = -nFξ.
At equilibrium, ∆G = 0, so ξ = 0, too.
At equilibrium, Q = K, since all reactants and products are present at their equilibrium concentrations.
This simplifies the Nernst equation to:
ξocell = [(RT)/nF] ln K
Now calculate a value for K.
You may need to use scientific notation to record your answer. If so, enter it as: 4E43 which is equivalent to 4x1043

• chemistry -

Use second equation

1.420- (-1.087)= .333
Use that as cell potential.

R=8.314
T=298
n= 6 mols electrons because you have to multiply the two reactions to get 6 electrons so you can cancel the electrons out
F=96,500

.333= 0.004279lnQ

divide both sides by .00427 to cancel it from the right side

.333/.00427=77.82

77.82=lnQ
enter in calculator 2nd and ln to get e^ (77.82) because you want to get ride of ln from the right side so its pushed to the left side as its inverse of e^ (77.82) and ln cancels out so youre left with Q.

## Similar Questions

1. ### Chemistry

If 0.870 mol of liquid Br2 and 720 mL of 0.958 M aqueous NaI are reacted stoichiometrically according to the balanced equation, how many grams of solid I2 are produced?
2. ### Chemistry!

A Galvanic cell runs on the following reaction: Co (s) + Cu2+ (aq) → Co2+ (aq) + Cu (s) Draw a diagram for this Galvanic cell, labeling the electron flow, the anode and cathode, and the positive and negative sides of the Galvanic …
3. ### chemistry

Using the half-reaction method, balance the redox reaction below. Show your work; partial credit will be given. I- + Br2 → IO3- + Br- Write the reduction and oxidation half-reactions. Balance them for atoms. Balance each of the …
4. ### Chemistry

Consider two cells, the first with Al and Ag electrodes, and the second with Zn and Ni electrodes, each in appropriate 1.00M solutions of their ions. If 2.10g of metal is plated in the voltaic cell, how much metal is plated in the …
5. ### chemistry

E degrees (V) A galvanic cell based on the following half reaction s Au3+ 3e- ----> Au 1.50 Mg2+ 2e- ------> Mg -2.37 The cell is set up at 25 C with [Mg2+] = 1.00 x 10^-5 M The cell potential is observed to be 4.01 V. Calculate …
6. ### Chemistry

Use the data given below to construct a Born - Haber cycle to determine the electron affinity of Br?
7. ### Chemistry

Given the following half-reactions and associated standard reduction potentials: AuBr−4(aq)+3e−→Au(s)+4Br−(aq) E∘red=−0.858V Eu3+(aq)+e−→Eu2+(aq) E∘red=−0.43V IO−(aq)+H2O(l)+2e−→I−(aq)+2OH−(aq) …
8. ### chemistry

Use the following pair of reduction half-reactions to design a galvanic cell. Then write in the proper coefficient for each of the species involved in the overall reaction. Water molecules and protons are not shown in the half-reactions, …
9. ### chemistry

Consider the following standard reduction potentials of some commonly used metals: ξo (V) Au3+ (aq) + 3 e- → Au (s) +1.50 Ag+ (aq) + e- → Ag (s) +0.80 Cu2+ (aq) + 2e- → Cu (s) +0.34 Fe3+ (aq) + 3e- → Fe …
10. ### chemistry

Which of the following half-reactions would occur at the anode of an electrochemical cell?

More Similar Questions