SIG FIGS

Science questions not covered in Chem 14A and 14B. Try to limit questions to chemistry (inorganic chemistry, physical chemistry, organic chemistry, biophysical chemistry, biochemistry, materials science, environmental chemistry).

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sarahtang4B
Posts: 132
Joined: Fri Sep 28, 2018 12:27 am

SIG FIGS

Postby sarahtang4B » Tue Jan 15, 2019 1:11 pm

What are the rules for sig figs when doing calculations for pH? do we always keep 2 digits after the decimal?

Elaine Pham 2E
Posts: 58
Joined: Fri Sep 28, 2018 12:28 am
Been upvoted: 1 time

Re: SIG FIGS

Postby Elaine Pham 2E » Tue Jan 15, 2019 1:24 pm

For doing sig figs with pH, you start counting the sigfigs after the decimal point. For example, a pH of 1.11 has 2 sig figs or a pH of 10.000 has 3 sig figs.

Irene Zhou 1E
Posts: 73
Joined: Fri Sep 28, 2018 12:18 am

Re: SIG FIGS

Postby Irene Zhou 1E » Tue Jan 15, 2019 11:25 pm

When considering sig figs for pH, begin counting the number of significant numbers after the decimal. This is because the pH of 1-14 is not based on error

Patrick Cai 1L
Posts: 93
Joined: Fri Sep 28, 2018 12:25 am

Re: SIG FIGS

Postby Patrick Cai 1L » Tue Jan 15, 2019 11:51 pm

The reason for this sig fig difference in calculations related to either pH or pOH can be seen on the Chem 14B website, under the link labeled "Everything you want to know about Significant Figures". Here, the concept of how floating point number is made is shown with respect to the mantissa, or the part of the number following the decimal point. Other sig fig questions can be typically answered here.

Brianna Brockman 1F
Posts: 60
Joined: Fri Sep 28, 2018 12:23 am

Re: SIG FIGS

Postby Brianna Brockman 1F » Sun Mar 17, 2019 6:36 pm

It depends on what's given to you in the problem. If the probelm give you numbers with 3 sig figs, do three.

Jaqueline Monreal 2L
Posts: 57
Joined: Fri Sep 28, 2018 12:28 am

Re: SIG FIGS

Postby Jaqueline Monreal 2L » Sun Mar 17, 2019 7:14 pm

it is usually two digits rounded


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