pH sig figs

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AKatukota
Posts: 100
Joined: Thu Jul 25, 2019 12:18 am

pH sig figs

Postby AKatukota » Mon Jan 20, 2020 1:27 pm

How do you determine how many significant figures to write when determining pH?

Tiffany_Chen 2K
Posts: 106
Joined: Fri Aug 30, 2019 12:15 am

Re: pH sig figs

Postby Tiffany_Chen 2K » Mon Jan 20, 2020 1:30 pm

For your final answer (if asked for pH), you want to have the least number of sig figs for the value past the decimal point. E.g. you are given 0.015M of something and that is the least number of sig figs. Your answer would be need two sig figs past the decimal point, e.g. 3.00

Emily Chirila 2E
Posts: 112
Joined: Sat Jul 20, 2019 12:16 am

Re: pH sig figs

Postby Emily Chirila 2E » Mon Jan 20, 2020 7:29 pm

pH sig figs start to count after the decimal point. So, if you have 2 sig figs in the given information for the problem, then your pH answer should have 2 sig figs AFTER the decimal point.

Harry Zhang 1B
Posts: 101
Joined: Sat Sep 14, 2019 12:16 am

Re: pH sig figs

Postby Harry Zhang 1B » Mon Jan 20, 2020 9:43 pm

In pH value, only the numbers after the decimal point count as sig.figs., so you need to write as many numbers after the decimal point as there are in the number of sig.figs. in the question.

Aarushi Solanki 4F
Posts: 107
Joined: Sat Jul 20, 2019 12:17 am

Re: pH sig figs

Postby Aarushi Solanki 4F » Mon Jan 20, 2020 9:47 pm

Only the numbers after the decimal matter when determining the number of significant figures to add. For example, if two sig figs are used in the question, then the answer should have two significant figures AFTER the decimal (ex: 5.41).

Hannah Romeo 1J
Posts: 58
Joined: Thu Jul 11, 2019 12:16 am

Re: pH sig figs

Postby Hannah Romeo 1J » Mon Jan 20, 2020 9:55 pm

I believe that it is two sig figs after the decimal place because pH + pOH = 14.00. Because, the sig fig rules for addition and subtraction indicate that your result can only be as accurate as the least precise digit, there are two sig figs after the decimal point.

Juana Abana 1G
Posts: 100
Joined: Wed Sep 18, 2019 12:15 am

Re: pH sig figs

Postby Juana Abana 1G » Mon Jan 20, 2020 10:26 pm

For the pH value only the numbers after the decimal point count as significant figures.

MTanikella_1K
Posts: 110
Joined: Sat Jul 20, 2019 12:16 am

Re: pH sig figs

Postby MTanikella_1K » Thu Jan 23, 2020 12:16 pm

Numbers after the decimal point count as significant figures for pH.

005384106
Posts: 101
Joined: Sat Aug 24, 2019 12:16 am

Re: pH sig figs

Postby 005384106 » Thu Jan 23, 2020 12:27 pm

does the amount of significant figures for the molar concentration determine the amount of significant figures used after the decimal place of a pH?

Mariana Fuentes 1L
Posts: 43
Joined: Wed Nov 15, 2017 3:00 am

Re: pH sig figs

Postby Mariana Fuentes 1L » Thu Jan 23, 2020 12:29 pm

2 significant figures from the decimal.


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