Entropy
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Entropy
Can we use the van't hoff equation to calculate entropy, or would we use a different equation to calculate entropy over a temperature change?
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Re: Entropy
This depends on which form of the Van't hoff equation you're using. You can use the van't hoff equation to indirectly solve for the enthalpy of a reaction over a given temperature range, since the equation relates two different equilibrium constants at two different temperatures with there being a factor of deltaH/R.
However, you could also use the form of the equation that relates one equilibrium constant to a reaction at a singular temperature, in which you're also able to solve for the entropy at that given temperature.
ln(K) = -deltaH/RT + deltaS/R
However, you could also use the form of the equation that relates one equilibrium constant to a reaction at a singular temperature, in which you're also able to solve for the entropy at that given temperature.
ln(K) = -deltaH/RT + deltaS/R
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Re: Entropy
This definitely would just depend on what you are given in a question. If it provides the values needed to solve for entropy I assume it's possible but typically the Van't Hoff equations are used to find K at different temperatures.
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Re: Entropy
A situation like this depends on the values that you are given, but I think that in most cases the delta G = delta H - T delta S would be best.
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Re: Entropy
I believe that entropy is constant when using the Van Hoff’s equation so you should apply different equation to calculate the change in entropy
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Re: Entropy
I don't think that using the Van't Hoff equation is the best way to calculate ΔS because the equation is set up such that the ΔS terms cancel. So I imagine you'd be left with an expression like x=x and the ΔS term falls off.
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Re: Entropy
Siwa Hwang 3G wrote:I believe that entropy is constant when using the Van Hoff’s equation so you should apply different equation to calculate the change in entropy
Actually, Professor Lavelle addressed this in Friday's lecture. Only change in entropy is constant when using Van't Hoff equations. Entropy will still change because it is temperature dependent.
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Re: Entropy
i would just stick to using vant hoff for K or the variables that are already in the equation
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Re: Entropy
Entropy is constant when using the van't Hoff equation, so I would probably suggest you use a different equation to find the entropy.
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Re: Entropy
It could depend, but the safest option is to always use delta G = delta H - T delta S to calculate entropy.
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Re: Entropy
It really depends on what values you are given in the problem. This equation is a bit more complicated so I would just use deltaG=deltaH-TdeltaS because it is more straightforward.
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