Textbook 6E.3
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Textbook 6E.3
In this question, it says "ignoring second deportations only when the approximation is justified." I was wondering what does it mean when it says approximation is justified?
Re: Textbook 6E.3
Hello,
Correct me if I’m misinterpreting your question but Dr. Lavelle mentioned we can justify our approximation if the percentage deprotonation is less than 5%. In the context of your quote, since K2 is really weak compared to K1, we usually have a good enough (<5%) calculation with our approximation. There is an exception with H2SO4 though!
Hopefully this helped.
Correct me if I’m misinterpreting your question but Dr. Lavelle mentioned we can justify our approximation if the percentage deprotonation is less than 5%. In the context of your quote, since K2 is really weak compared to K1, we usually have a good enough (<5%) calculation with our approximation. There is an exception with H2SO4 though!
Hopefully this helped.
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Re: Textbook 6E.3
Hello,
When we have an equilibrium constant that is less than 10^-3, then we can approximate the change in reactants. This is because the decrease in reactants is extremely small compared to the initial amount of reactant. Approximation makes these problems a lot simpler, especially when it comes to cubic equations. However, in order for this approximation to be valid (or justified, as you mentioned), the percent ionization must be less than 5%.
Hope this helps!
When we have an equilibrium constant that is less than 10^-3, then we can approximate the change in reactants. This is because the decrease in reactants is extremely small compared to the initial amount of reactant. Approximation makes these problems a lot simpler, especially when it comes to cubic equations. However, in order for this approximation to be valid (or justified, as you mentioned), the percent ionization must be less than 5%.
Hope this helps!
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Re: Textbook 6E.3
For polyprotic acids:
Estimate the pH of a polyprotic acid for which all deprotonations are weak by using only the first deprotonation equilibrium and assuming that further deprotonation is insignificant (assuming the percent ionization is less than 5%). An exception is sulfuric acid, the only common polyprotic acid that is a strong acid in its first deprotonation.
Estimate the pH of a polyprotic acid for which all deprotonations are weak by using only the first deprotonation equilibrium and assuming that further deprotonation is insignificant (assuming the percent ionization is less than 5%). An exception is sulfuric acid, the only common polyprotic acid that is a strong acid in its first deprotonation.
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