"AmmoniaConcentration" package in 'R'

[Dhamnekar Win,odd]

Please read here and the answer the following questions if you know:

How did the author derive the following equations?

pKa = 0.09018 + 2727.92/T


f = 1/(10(pKa − pH) + 1)

How would you interpret the answers given by 'R' using this package?
 How is NH₃_mgL computed in 'R' using this package?

What is the denomination of total ammonia in the argument given by the author in the examples ? Is it mol/L or in grams? 

 

[joigus]

I know the answer to the 1st one: It's the linearised Arrhenius equation:

https://en.wikipedia.org/wiki/Arrhenius_plot

which relates pH, pka, and activation energy with absolute temperature.

I hope that helps.

[exchemist]

1 hour ago, joigus said:

I know the answer to the 1st one: It's the linearised Arrhenius equation:

https://en.wikipedia.org/wiki/Arrhenius_plot

which relates pH, pka, and activation energy with absolute temperature.

I hope that helps.

Shome mishtake shurely?

This doesn't seem to me to be about reaction rates. pKa relates to the equilibrium constant for dissociation of an acid.

I would think -RTlnK =  ΔG = ΔH - TΔS would be where the first equation comes from, wouldn't it? 

Regarding "f", seeing pH and pKa subtracted from each other reminds me of the Henderson-Hasselbalch equation. 

Perhaps our friend can take things from there......... 

(On past form this may be some kind of homework, so I'm not going to get enmeshed in the algebra myself.)

Edited April 16, 2022 by exchemist

[Dhamnekar Win,odd]

41 minutes ago, exchemist said:

Shome mishtake shurely?

This doesn't seem to me to be about reaction rates. pKa relates to the equilibrium constant for dissociation of an acid.

I would think -RTlnK =  ΔG = ΔH - TΔS would be where the first equation comes from, wouldn't it? 

Regarding "f", seeing pH and pKa subtracted from each other reminds me of the Henderson-Hasselbalch equation. 

Perhaps our friend can take things from there......... 

(On past form this may be some kind of homework, so I'm not going to get enmeshed in the algebra myself.)

     Rectified  equation of f(fraction of NH₃)= [math] \frac{1}{10^{(pKa-pH)} +1}[/math]

[joigus]

54 minutes ago, exchemist said:

Shome mishtake shurely?

This doesn't seem to me to be about reaction rates. pKa relates to the equilibrium constant for dissociation of an acid.

I would think -RTlnK =  ΔG = ΔH - TΔS would be where the first equation comes from, wouldn't it? 

Regarding "f", seeing pH and pKa subtracted from each other reminds me of the Henderson-Hasselbalch equation. 

Perhaps our friend can take things from there......... 

(On past form this may be some kind of homework, so I'm not going to get enmeshed in the algebra myself.)

I stand corrected. It sure looks a lot like the Henderson-Hasselbach equation. The base-10 logs should've given me a clue.

 

[exchemist]

46 minutes ago, Dhamnekar Win,odd said:

     Rectified  equation of f(fraction of NH₃)= 110(pKa−pH)+1

OK. And what are pKa and pH, mathematically speaking?  

[Dhamnekar Win,odd]

18 hours ago, exchemist said:

OK. And what are pKa and pH, mathematically speaking?  

pK_a = -Log(k_a), pH = pK_a + log (NH₃/(NH₃ + NH₄⁺)). So, K_a= 4.33504889257e-10

Now, [math]\frac{1}{10^{pK_a- pH}}=\frac{NH_3}{NH_3 + NH_4^+}=3.44345173426e-3[/math]  Why 1 is added to denominator NH₃ + NH₄⁺?   

 

I think Emerson et al. developed the equation pK_a = 0.09018 + 2729.92/T on experimental basis.

Edited April 17, 2022 by Dhamnekar Win,odd

[Dhamnekar Win,odd]

 I tag this question as 'SOLVED' as I got correct  answers to all my questions. ☺️

[exchemist]

1 hour ago, Dhamnekar Win,odd said:

 I tag this question as 'SOLVED' as I got correct  answers to all my questions. ☺️

Well done! 

I look forward to your next enquiry. I'm having to dredge things up from the depths of my memory - which is a good process.