Temperature's affect on Galvanic

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In summary, the conversation discusses the effect of temperature on voltage in an electrochemical cell, specifically in standard 1 M solutions. The Nernst equation is mentioned, although it has not been taught in class. The speaker mentions that in their high school experiments, they found that the voltage increases by .012 V/k with temperature. However, the speaker is unsure about the results due to less than ideal lab conditions. The practical and theoretical effects of temperature on voltage are also discussed, with the practical aspect being that higher temperatures increase reaction rate and the theoretical aspect being that higher temperatures should decrease voltage based on the Nernst equation. The speaker asks for help in understanding when lnQ is positive or negative and comes to the conclusion that their aluminum
  • #1
Hockeystar
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Homework Statement


Determine the affect of temperature on voltage on an electrochemical cell in standard 1 M solutions.


Homework Equations



Only equation in high school chem: Ne=It/F

This Nernst equation keeps on coming up even though we haven't learned it in class.

Ecell=E°cell- (RT/nF) lnQ.


The Attempt at a Solution



Our high school class did 6 experiments and we came up with the conclusion that the voltage increases .012 V/k. The High school lab conditions weren't ideal and I don't really trust the results.I'm all confused now.

Pratically, as temperature increases the reaction rate should increases. This is why car batteries have trouble starting in winter and people keep batteries in the fridge.

Theoretically, as temperature increase, the voltage should drop based upon Nernst. The non-sportaneous reaction of the cathode oxidizing will happen more readily and counteract the oxidation of the anode.

Help is much appreciated.
 
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  • #2
Hockeystar said:
Ecell=E°cell- (RT/nF) lnQ.

Under what conditions is lnQ positive, and under what conditions is it negative?
 
  • #3
Ahh I got it. Seems like the aluminum solution was off in class and that's why it has the biggest rate of change.
 

1. How does temperature affect the rate of a galvanic reaction?

Temperature has a direct impact on the rate of a galvanic reaction. Generally, an increase in temperature will result in an increase in reaction rate, while a decrease in temperature will result in a decrease in reaction rate. This is because temperature affects the kinetic energy of the reactant molecules, leading to more frequent and energetic collisions, which in turn increases the likelihood of successful reactions.

2. What is the temperature coefficient for galvanic reactions?

The temperature coefficient for galvanic reactions is a measure of how much the rate of the reaction changes with a change in temperature. It is typically represented by the symbol Q10, and is calculated by dividing the reaction rate at a higher temperature by the reaction rate at a lower temperature. A Q10 value of 2 means that the reaction rate doubles for every 10 degree Celsius increase in temperature.

3. How does temperature affect the equilibrium constant for a galvanic reaction?

The equilibrium constant, also known as the K value, is a measure of the relative concentrations of reactants and products at equilibrium. Temperature affects the equilibrium constant for a galvanic reaction by shifting the equilibrium towards the products at higher temperatures and towards the reactants at lower temperatures. This is due to the fact that the equilibrium constant is dependent on the reaction's enthalpy and entropy, both of which are affected by temperature.

4. Can temperature have a negative effect on a galvanic reaction?

Yes, in some cases, temperature can have a negative effect on a galvanic reaction. This is especially true for reactions that involve biological molecules, such as enzymes. These reactions often have an optimal temperature at which they function most efficiently. Any increase or decrease in temperature beyond this optimal point can lead to a decrease in reaction rate or even denaturation of the enzyme, resulting in a negative effect on the reaction.

5. How can the effect of temperature on galvanic reactions be controlled?

The effect of temperature on galvanic reactions can be controlled by using a temperature-controlled environment, such as a water bath or a temperature-controlled chamber. This allows for precise control of the reaction temperature and can help maintain a steady reaction rate. Additionally, the use of catalysts can also help mitigate the effects of temperature on galvanic reactions by lowering the activation energy required for the reaction to occur.

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