## Are all pH calculations done to 2 decimal places or do we use sig figs in pH calculations? [ENDORSED]

Henri_de_Guzman_3L
Posts: 88
Joined: Fri Sep 28, 2018 12:25 am

### Are all pH calculations done to 2 decimal places or do we use sig figs in pH calculations?

For example 6B.5c in the 7th edition textbook asks us to calculate the pH for 0.0092 M Ba(OH)2. This is 2 sig figs but the answer in the back gives 12.96. Should the answer instead be 13?

anthony_trieu2L
Posts: 60
Joined: Fri Sep 28, 2018 12:29 am

### Re: Are all pH calculations done to 2 decimal places or do we use sig figs in pH calculations?  [ENDORSED]

For pH calculations, the sig figs are only accounted for after the decimal point. In this case, since there are two sig figs in 0.0092 M Ba(OH)2, the final answer should present two digits after the decimal point. Thus, 12.96 is correct.

RandallNeeDis3K
Posts: 34
Joined: Fri Sep 28, 2018 12:25 am

### Re: Are all pH calculations done to 2 decimal places or do we use sig figs in pH calculations?

pH calculations only follow sig figs after the decimal point! so two sig figs after the decimal point makes sense.

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