Calculating pKa and pKb

[006033476]

when calculating pKa and pKb with the given pH will it always consist of using the formula [H30+]= 10^-pH and pKb: pOH= 14-pH then OH-= 14-pOH? Or when will the formula change because I still get a little confused when using the formulas?

[faith14B]

The formula does not change. However depending on the temperature kw may change.

[Janelle2E]

To calculate pKa when pH is known, you can use pKa= pH +log ([A-]/[HA]). [A-] represents the concentration of the conjugate base and [HA] represents the concentration of the acid. Then to find pKb you must subtract the pKa from 14, so pKb= 14-pKa H+.

[105561735]

In summary, the formula never changes if given the pH and trying to find the pOH and vice versa. The only time you may need additional corrections is in non-standard conditions such at the effects that different concentrations may have or temperature