## Sig Figs

Dina Geotas 4A
Posts: 61
Joined: Fri Sep 28, 2018 12:29 am

### Sig Figs

What are the sig fig rules for calculating pH and pOH? thank you!

Grace Kim 1J
Posts: 60
Joined: Fri Sep 28, 2018 12:18 am
Been upvoted: 1 time

### Re: Sig Figs

When calculating pH and pOH, count the number of sig figs given in the concentration and the pH/pOH should have that number of sig figs after the decimal. For example, if the pH=-log(1.4x 10^-6) then pH = 5.85 (two sig figs in 1.4 x 10^-6 and two after the decimal in 5.85).

Hope this helped!

Ian Marquez 2K
Posts: 66
Joined: Fri Sep 28, 2018 12:16 am
Been upvoted: 2 times

### Re: Sig Figs

Like said above, sig figs are a little bit different when dealing with pH and pOH because of what the log function does. A good rule is to just count sig figs in pH and pOH as the figures after the decimal point. This means that a pH of 1.2 has only one sigfig and 1.23 would have two. This rule only applies to pH and pOH as well as any other times you would apply a log such as pKa and pKb.