https://cran.r-project.org/web/packages/AmmoniaConcentration/AmmoniaConcentration.pdfHow 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 NH

_{3}_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?