## 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).

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

### SIG FIGS

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

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

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

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

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

it is usually two digits rounded