Enthelpy of Dissolution vs. Enthelpy of Solution

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Discussion Overview

The discussion revolves around the concepts of enthalpy of dissolution and enthalpy of solution, particularly in the context of measuring the enthalpy changes during the dissolution of salts in water. Participants explore the definitions, implications of enthalpy values, and discrepancies between measured and reference values.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant questions the difference between enthalpy of dissolution and enthalpy of solution, noting discrepancies between their measured values and those found in reference materials.
  • The same participant expresses confusion about the relationship between endothermic reactions and negative enthalpy values, suggesting a potential misunderstanding of what enthalpy of dissolution indicates.
  • Another participant asserts that negative enthalpy values indicate exothermicity and claims that enthalpy of solution and dissolution are equivalent, referring to the heat change when one mole of solute dissolves.
  • Subsequent posts introduce a tone of skepticism and humor, with one participant questioning the seriousness of the previous claim and another playfully admonishing them for lying.

Areas of Agreement / Disagreement

There is disagreement regarding the definitions and implications of enthalpy of dissolution versus enthalpy of solution, as well as the interpretation of negative enthalpy values. The discussion remains unresolved with multiple competing views presented.

Contextual Notes

Participants have not reached a consensus on the definitions or implications of enthalpy values, and there is uncertainty regarding the relationship between endothermic reactions and enthalpy changes.

Wailing Fungus
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What is the difference between enthalpy of dissolution and enthalpy of solution?

I have a lab where I have to measure the change in enthalpy of dissolution of several salts in water. I found the change in enthalpy, however I am supposed to compare them with the real values. I looked in the CRC handbook and there was only a table with changes in enthalpies of solution, these were different values than the ones I got.

Another thing that I do not undestand is that my reactions were endothermic but my enthalpies of dissolution were all negative. Doesn't enthalpy change indicate if a reaction is exothermic or endothermic? Unless enthalpy of dissolution indicates something else. I used the following equations:

q = CdT where C is the calorimeter constant

then

dH = q / n where dH is the change in enthalpy of dissolution
 
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Negative values indicate a release of energy and exothermicity. Enthalpy of solution and dissolution are the same thing- heat change when one mole of solute dissolves
 
Are you serious?
 
No I'm lying.
 
You shouldn't lie Cesium, it's probably against some policy here. Hehe.
 

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