Van't Hoff Approach to Finding ∆H and ∆S

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In summary, the conversation is discussing the Van't Hoff equation and its use in calculating the enthalpy change for a reaction. The formula includes ∆Ho, representing the standard enthalpy change for 1 mole of reactant at 298K. This means that T1 must always be 298K in order to use the formula. To find the ∆Ho for a reaction, one would plug 298K into T1 and the given value into KT1, and then any other pair of values from the table into T2 and KT2. However, it is noted that the ∆H is always assumed to be constant with temperature in this equation, which is a limitation of the equation.
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ampakine
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Heres the question:
[PLAIN]http://img194.imageshack.us/img194/9042/vanthoff.png
and here's the Van't Hoff equation (the form I like to use):
[PLAIN]http://img703.imageshack.us/img703/1577/vtequation.png
I'm a bit confused about what's going on here. I see the formula includes ∆Ho, meaning the enthalpy change for 1 mole of reactant at 298K. Does that mean to use this formula T1 always has to be 298K? In other words to get the ∆Ho for the reaction would I just plug 298K into T1 and 4.25 x 10-7 into KT1 then plug any other pair of values from that table into T2 and KT2?
 
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The ∆H is always assumed to be constant with temp in this equation (standard enthalpy change), which is an obvious downside to the relation. If you derive it from
(d ln(K)) / (d 1/T) = -∆Ho/R you will find that from the integration.
 

1. What is the Van't Hoff Approach to finding ∆H and ∆S?

The Van't Hoff Approach is a method used in thermodynamics to calculate the changes in enthalpy (∆H) and entropy (∆S) of a chemical reaction. It is based on the relationship between temperature and equilibrium constant.

2. How is the Van't Hoff Approach used to find ∆H and ∆S?

The Van't Hoff Approach involves plotting ln(K) against 1/T (where K is the equilibrium constant and T is the temperature in Kelvin) and using the slope and intercept of the resulting line to calculate ∆H and ∆S.

3. What is the significance of using the Van't Hoff Approach?

This approach allows for the determination of thermodynamic parameters without directly measuring them, making it a useful tool for studying chemical reactions and predicting their behavior under different conditions.

4. What are the limitations of the Van't Hoff Approach?

The Van't Hoff Approach assumes that the reaction is taking place in a closed system at equilibrium, and does not take into account factors such as non-ideal behavior or changes in heat capacity with temperature. It is also only applicable to reactions that are reversible and follow the van't Hoff equation.

5. Can the Van't Hoff Approach be used for all types of reactions?

No, the Van't Hoff Approach is only applicable to reactions that are reversible and follow the van't Hoff equation. It cannot be used for reactions that do not have a well-defined equilibrium constant or for reactions that do not follow the ideal gas law.

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