Sig Figs

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

Sig Figs

Postby Dina Geotas 4A » Wed Jan 23, 2019 4:13 pm

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

Grace Kim 1J
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Joined: Fri Sep 28, 2018 12:18 am
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Re: Sig Figs

Postby Grace Kim 1J » Wed Jan 23, 2019 4:18 pm

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
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Re: Sig Figs

Postby Ian Marquez 2K » Wed Jan 23, 2019 4:20 pm

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.

Vanadium Wang 4H
Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

Re: Sig Figs

Postby Vanadium Wang 4H » Thu Jan 24, 2019 12:01 am

When calculating pH and pOH, sig figs are calculated from the initial concentration and applied after the decimal of the pH/pOH


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