Sig Figs for pH/pOH

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LBacker_2E
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Sig Figs for pH/pOH

Postby LBacker_2E » Mon Jan 20, 2020 4:49 pm

Is there a special way to calculate sig figs for pH and pOH? I feel like this might have been mentioned in class, but now I am getting confused if this is for my chem lab instead? Do you determine sig figs based off of the decimal places of the numbers you are given or vice versa?

asannajust_1J
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Re: Sig Figs for pH/pOH

Postby asannajust_1J » Mon Jan 20, 2020 4:56 pm

number of sig figs in a pH or pOH only count after the decimal. For pH=3.489, there would be three sig figs since there are 3 decimal place. If the question is only 1 sig fig then the pH can be reported to 1 decimal place. Hope this makes sense!

MAC 4G
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Re: Sig Figs for pH/pOH

Postby MAC 4G » Mon Jan 20, 2020 5:14 pm

Generally, you would use the smallest number of sig figs you were given in a problem. For example, if you used a ICE box to find that x is 4.22*10^-5, then you're pH or pOH should have 3 sig figs (2 numbers after the decimal) like 4.38.

EMurphy_2L
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Re: Sig Figs for pH/pOH

Postby EMurphy_2L » Mon Jan 20, 2020 5:43 pm

the number of sig figs in the problem asked is the number of decimal places you include after taking a log (which applies to pH and pOH)

stephaniekim2K
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Re: Sig Figs for pH/pOH

Postby stephaniekim2K » Tue Jan 21, 2020 1:08 am

The number of sig figs to the answer of a log is the amount of sig figs after the decimal of the number you took the log of.

Minh Ngo 4G
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Re: Sig Figs for pH/pOH

Postby Minh Ngo 4G » Tue Jan 21, 2020 10:21 am

Basically the digit before the “.” doesn’t count as sig fig. For example, pH =3.98 only has 2 sig fig. You count after the decimal place. However, the concentration of OH or H3O follow the usual rule.

nicole-2B
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Re: Sig Figs for pH/pOH

Postby nicole-2B » Tue Jan 21, 2020 8:56 pm

significant figures for pH/pOH only counts after the decimal.

Renee Grange 1I
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Re: Sig Figs for pH/pOH

Postby Renee Grange 1I » Tue Jan 21, 2020 11:08 pm

in pH/pOH the you only count sig figs after the decimal point.


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