Calc Standard Voltage, Eq Const, & Voltage @ 25°C for Sn + 2Ag+ --> Sn2+ + 2Ag

In summary, the standard voltage for the reaction Sn + 2Ag+ → Sn2+ + 2Ag at 25°C is 0.64V. The equilibrium constant for this reaction is 1.09 x 10^6 at 25°C. Temperature affects the standard voltage for this reaction by decreasing it with increasing temperature. However, the temperature coefficient of this reaction is negative, meaning that the decrease is relatively small. This reaction is spontaneous at 25°C due to its positive standard voltage. The silver ions (Ag+) act as the oxidizing agent in this reaction, being reduced to elemental silver while the tin (Sn) is oxidized to Sn2+. This transfer of electrons drives the reaction forward.
  • #1
Rockstar2
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Homework Statement


Sn + 2 Ag+ --> Sn2+ + 2 Ag

a) Calculate the standard voltage of a cell involving the system above. (I got +0.94 Volts).

b) What is the equilibrium constant for the system above? (I got 5.71 E 31)

c) Calculate the voltage at 25 degrees celsius of a cell involving the system above when the concentration of Ag+ is 0.0010 molar and that of Sn+2 is 0.20 molar. (I got + 0.783 volts)

Homework Equations



Eocell = Ered - Eox

Nernst Equation - Ecell = Eocell - 0.0592/n logQ

The Attempt at a Solution



Above.
 
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  • #2


Hello, thank you for your post. Here are my thoughts on your solutions:

a) I agree with your calculation of +0.94 volts for the standard voltage of the cell.

b) However, I believe there is an error in your calculation for the equilibrium constant. The equilibrium constant, K, is equal to the ratio of the forward and reverse rate constants, not the voltage. To calculate the equilibrium constant, you would need to use the Nernst equation to calculate the voltage at equilibrium (Eeq), and then use that value to solve for K using the equation Eeq = 0.0592/n logK. The correct equilibrium constant for this reaction is actually 2.71 x 10^31.

c) For part c), I believe your calculation is correct. Using the Nernst equation with the given concentrations, I also get a voltage of +0.783 volts at 25 degrees Celsius. Great job on this problem!
 

1. What is the standard voltage for the reaction Sn + 2Ag+ → Sn2+ + 2Ag at 25°C?

The standard voltage for this reaction is 0.64V at 25°C. This value is determined by the difference in standard reduction potentials of the reactants and products.

2. What is the equilibrium constant for the reaction Sn + 2Ag+ → Sn2+ + 2Ag at 25°C?

The equilibrium constant, also known as Keq, is a measure of the relative concentrations of products and reactants at equilibrium. For this reaction, the equilibrium constant is 1.09 x 106 at 25°C.

3. How does temperature affect the standard voltage for this reaction?

As temperature increases, the standard voltage for this reaction decreases. This is due to the change in the enthalpy and entropy of the reaction, which affects the Gibbs free energy and subsequently the standard voltage. However, the temperature coefficient of this reaction is negative, meaning that the decrease in standard voltage with increasing temperature is relatively small.

4. Is this reaction spontaneous at 25°C?

Yes, this reaction is spontaneous at 25°C. The standard voltage for this reaction is positive, meaning that the reaction is thermodynamically favorable to proceed in the forward direction.

5. What is the role of the silver ions in this reaction?

The silver ions, or Ag+, act as the oxidizing agent in this reaction. They are reduced to elemental silver (Ag) while the tin (Sn) is oxidized to Sn2+. This transfer of electrons from tin to silver is what drives the reaction forward.

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