Sig Figs for logarithmic funcitons

Gabriella Bates 2L
Posts: 113
Joined: Thu Jul 11, 2019 12:15 am

Sig Figs for logarithmic funcitons

How do sig figs work on logarithmic functions when doing pH calculations?

zachary_nhem_4I
Posts: 57
Joined: Sat Aug 17, 2019 12:18 am

Re: Sig Figs for logarithmic funcitons

I'm sure the number of sig figs would be the same as the concentration that is given

Mitchell Koss 4G
Posts: 128
Joined: Sat Jul 20, 2019 12:17 am

Re: Sig Figs for logarithmic funcitons

Sig fig rules are standard for any kind of problem

Sebastian Lee 1L
Posts: 157
Joined: Fri Aug 09, 2019 12:15 am
Been upvoted: 1 time

Re: Sig Figs for logarithmic funcitons

Actually, the sig figs for pH are a little different than normal. Essentially, if you are calculating the pH from a given concentration, the number of sig figs in the concentration is the number of sig figs you put AFTER the decimal point in the pH.

For example, if I was given a 3.14 * 10-2 M solution of HCl, I would find the pH to be 1.503. This is because the concentration has 3 sig figs so I would need 3 digits AFTER the decimal point on my pH. The 1 in front of the decimal does not count.

Michelle Le 1J
Posts: 50
Joined: Fri Aug 09, 2019 12:16 am

Re: Sig Figs for logarithmic funcitons

When you get the concentration and are trying to solve the pH, you would count how many sig figs the concentration has so for your answer, that would be the amount of numbers after the decimal point in your pH.

005321227
Posts: 90
Joined: Sat Sep 07, 2019 12:15 am

Re: Sig Figs for logarithmic funcitons

count the sig figs AFTER your decimal :)

rohun2H
Posts: 100
Joined: Wed Sep 18, 2019 12:19 am

Re: Sig Figs for logarithmic funcitons

I believe sig figs are also counted after the decimal when provided a pH and you are asked to give some numerical number, say a concentration for example. It was briefly mentioned by my TA.