sig figs

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Alyssa Bryan 3F
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Joined: Fri Sep 28, 2018 12:26 am
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sig figs

Postby Alyssa Bryan 3F » Sat Dec 08, 2018 11:57 pm

In high school, I was taught to add a sig fig when you take the -log to calculate the pH; however, there have been different things said about sig figs for this class regarding this topic. What is the expected rule for sig figs when taking the log that I should follow?

Henry_Phan_4L
Posts: 68
Joined: Fri Sep 28, 2018 12:24 am

Re: sig figs

Postby Henry_Phan_4L » Sun Dec 09, 2018 12:02 am

Based on my understanding it's roughly the same as what the problem gives. So if the concentration was 4.20 x 10^-6 mol then the pH would be 5.38.

keyaluo4C
Posts: 54
Joined: Fri Sep 28, 2018 12:17 am

Re: sig figs

Postby keyaluo4C » Sun Dec 09, 2018 12:12 am

Sig figs for pH are only calculated after the decimal. For example, a ph of 4.52 would have 2 sig figs.

Manas_Varma_4B
Posts: 30
Joined: Fri Sep 28, 2018 12:29 am

Re: sig figs

Postby Manas_Varma_4B » Sun Dec 09, 2018 2:25 pm

I personally just round off to sig figs at the very end of the problem.

Brian Kwak 1D
Posts: 88
Joined: Fri Sep 28, 2018 12:17 am

Re: sig figs

Postby Brian Kwak 1D » Thu Jan 17, 2019 10:27 am

I posted a photo further specifying significant figures for logs. But as it states on dr Lavelles PDF of “More on Significant figures” how ever many significant figures in the number your calculating is how ever many significant figures you have after the calculation.
Attachments
AD1C1BBF-F2C1-4AE4-A29E-CEC5582F39CE.png
Here is a pdf of “More on significant figures” on Dr. Lavelles website.


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