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Topic: Voltage change when temperature is changes in a galvanic cell?  (Read 828 times)

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Offline crustd

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Does the voltage change with temperature if the concentration of the solutions is the same in the galvanic cell? Based on the Nernst Equation, if the reaction quotient is 1, lnQr becomes 0, and thus the voltage equals standard cell potential regardless of temperature. Is this correct? I performed an experiment where I changed the temperature of a daniell cell, where both solutions were at 0.5 moldm3, and the results showed a slight increase in voltage as temperature increased. Is this due to the increase in resistance as temperature increases?

If I want to see how the nernst equation models the change of voltage in a galvanic cell, I'd have to have a reaction quotient that is not 1, is that correct? What would be the relationship between temperature and voltage if performed at a reaction quotient above 1?

Offline ACETAT

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Re: Voltage change when temperature is changes in a galvanic cell?
« Reply #1 on: May 17, 2021, 12:05:08 PM »
It will, check the original formula for Nernst equation  you will find the temperature in it.

Offline crustd

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Re: Voltage change when temperature is changes in a galvanic cell?
« Reply #2 on: May 17, 2021, 12:41:47 PM »
It will, check the original formula for Nernst equation  you will find the temperature in it.

I'm sorry, but when the reaction quotient is 1, doesn't lnQ become 0? Doesn't that get multiplied with the RT part of the equation, thus making whatever the temperature is 0 anyway?

Offline ACETAT

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Re: Voltage change when temperature is changes in a galvanic cell?
« Reply #3 on: May 17, 2021, 02:06:28 PM »
Then you have only the standard potential. There is no Temperature.
You was talking about the Daniel element and you have solutions of zinc and copper sulfate, which change during process.

Offline mjc123

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