Entropy related to Enthalpy
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Entropy related to Enthalpy
In outline 4, there is a bullet saying we should know how to "show how ∆S is related to ∆H for a change at constant temperature and pressure and explain the
relationship". I am confused as to which equation this is referring to and wanted to make sure I understand the right connection I should be making in terms of entropy and enthalpy?
relationship". I am confused as to which equation this is referring to and wanted to make sure I understand the right connection I should be making in terms of entropy and enthalpy?
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Re: Entropy related to Enthalpy
That is Gibbs free energy equation! It is applicable at constant temperature and pressure. deltaG = deltaH - TdeltaS
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Re: Entropy related to Enthalpy
Another thing to keep in mind is that for the Gibbs Free Energy equation, the T must be a constant temperature and make sure your G, S, and H values are all in either kJ or J and your T is in Kelvin.
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Re: Entropy related to Enthalpy
You can also represent the relationship between entropy and enthalpy using the formula ΔS = ΔH/T at temperature T. ΔH would usually be q, but q = ΔH at constant pressure.
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Re: Entropy related to Enthalpy
you could look at the gibbs free energy equation where T must be constant and in K.
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Re: Entropy related to Enthalpy
It's referencing Gibbs Free Energy! This shows that delta G = delta H - T delta S
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Re: Entropy related to Enthalpy
The two equations you can use for this are:
1) ΔG= ΔH - TΔS or ΔS = -(ΔG - ΔH)/T or ΔH = ΔG + TΔS
2) ΔS= −ΔH/T or ΔH = -ΔST
1) ΔG= ΔH - TΔS or ΔS = -(ΔG - ΔH)/T or ΔH = ΔG + TΔS
2) ΔS= −ΔH/T or ΔH = -ΔST
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Re: Entropy related to Enthalpy
Hello, an equation relating entropy with enthalpy is the Gibbs free energy equation. dG= dH - TdS
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Re: Entropy related to Enthalpy
To add on, the temperature will only need to be factored in to determine spontaneity when ∆S and ∆H are the same sign (one is negative and the other is positive). Using the equation, when ∆S and ∆H are both negative, the reaction will be spontaneous only at a lower threshold temperature. When ∆H and ∆S are both positive, the reaction will be spontaneous only at a higher threshold temperature.
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Re: Entropy related to Enthalpy
I think that it might be referring to the Gibbs free energy equation which is delta G= Delta H - T(DeltaS)
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Re: Entropy related to Enthalpy
That would be Gibbs free energy equation in which (change in Gibbs free energy) is equal to (change in enthalpy) minus (temperature in Kelvins times change in entropy).
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Re: Entropy related to Enthalpy
The relationship between entropy and enthalpy can be related by Gibb's Free Energy Equation. This equation is delta(G) = delta(H) - Temperature x delta(S), where entropy is represented by delta(S) and enthalpy is represented by delta(H). It is also worth noting that a rise in temperature (+H) is associated with a rise in disorder (+S), while a decrease in temperature is associated with an increase of order (-S).
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Re: Entropy related to Enthalpy
Hi! You would use the Gibbs Free Energy equation to find the relationship between entropy and enthalpy. The equation is deltaG=deltaH-T*deltaS
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Re: Entropy related to Enthalpy
Delta S relates to delta T in the concept of Gibbs free energy, given by the equation deltaG = deltaH - T*deltaS
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Re: Entropy related to Enthalpy
Hi! I was confused about this too, but I think they can be related through Gibbs Free Energy, which is determined by the equation ΔG = ΔH - TΔS. Hope this helps!
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Re: Entropy related to Enthalpy
Hi Joshua, I believe this concept is referring to Gibbs Free Energy, where deltaG = deltaH - T*deltaS, where T = temp. In this equation, temperature and pressure are both constant. Hope this helps!
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