Van't Hoff equation

[Jazlyn Romero 1I]

When do we use the van't hoff equation vs deltaG= -RTlnK when solving for the equilibrium constant?

[Kelly Singh]

I think they're virtually the same, but it might depend on what information you are given.

[Mikayla James 2A]

Hi! The Van't Hoff Equation is just derived from the ΔG°=-RTlnK equation where the standard Gibbs Free Energy equation, ΔG°=ΔH°-TΔS°, is substituted for ΔG°to get ΔH°-TΔS°=-RTlnK and then manipulated to arrive at the Van't Hoff equation. So they both should arrive at the same solution, but I think that you would use one or the other depending on the information given. Hope this helps!

[Annabella_Amato_1I]

Usually you use the Van't Hoff equation if the question concerns two K values at separate temperatures. For example, you could be given a K value at one temperature and are asked to find the K value at a different temperature using Van't Hoff. Another indication that you would need to use it is if the question provides the standard enthalpy of reaction, since this is necessary for Van't Hoff but not used in ΔG°=-RTlnK.

[Yu Jin Kwon 3L]

As the others have said before, you would use the Van't Hoff equation to find particularly K1 at T1 given K2 and T2 (or any derivation of that) OR you can directly find deltaH using the Van't Hoff equation given K1 at T1 and K2 and T2. The deltaG = -RTlnK can only give you a K at one T and you would have to do multiple steps to find deltaH.

Hope this helps!

[Vince Li 2A]

The Van't Hoff equation allows you to calculate K at a different temperature, given the initial temperature and initial K and the final temperature. The other equation provided only helps you calculate the K, given that you know the final temperature, and the Gibbs free energy. Comparing the two, the Van't Hoff equation allows you to find K with more applicable, attainable, and measurable information, such as temperature. The other equation requires you to find the Gibbs free energy.

[Jarrett Sung 3B]

The Van't Hoff equation is derived from deltaG = -RTlnK, but it's used when you find multiple temperatures and are trying to find the K value at one of those temps. Using either one just depends on the information given in a question.

[Bella Bursulaya 3G]

The Van't Hoff equation is used when you have two different temperature values, and you want to find the K at the new temperature. -RTlnK is used when you want to find the K value at a specific, constant temperature. If your temperature is not changing, then you can use it.

[Shreyank Kadadi 3K]

The van't Hoff equation is most useful when given two different temperature values. In most other cases, both equations work!

[Gian Boco 2G]

Typically use Van't Hoff when given two temperatures/two K values

[Muskaan Abdul-Sattar]

I believe the Van't Hoff equation is most applicable when given two different temperatures and attempting to solve for K at one of the two temperatures. Hope that makes sense!

[Tara Cumiskey 3K]

You usually use Van't Hoff when given two different temperatures.

[Debie_Morales1D]

Both equations give us entropy and enthalpy, however we decide which to use based on the Information given. van't Hoff equation is best when there are two temps given.

[andreagutierrez 3K]

Van't equation is typically used when trying to differentiate between two temperatures of a k value. Hopefully this helps!(: