1/30 Thoughts
Hey everyone, so I don't know about you but it was pretty interesting to see today how there is a huge difference between the average bond enthalpy values and the change of energy of the formation of a compound at SATP. Who would have thought that the averages would cause such a large difference when conducting calculations.
What I find interesting is the fact that no matter how many steps you take in order to attain a certain product, the change in enthalpy will stay the same since any compounds formed between steps will simply cancel one another out. We should be really thankful that enthalpy is a state function since that saves us a lot of effort. This was probably in Hess's mind when he was developing his law and it is extremely useful since as chemists we tend to be lazy. What do you all think about this?
Thanks, Matt! Sometimes the result predicted by the bond enthalpy (BE) method is really close to the result predicted by the heat of formation (deltaHf) method for determining heat of reaction. Even on your practice sheet, #1, the results differ by only 10 kJ/mol. And, yep, taking advantage of state properties to "save effort" is the kind of efficiency that "lazy" chemists really like!
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