## Standard Cell Potential Significant Figures on Midterm

Ranger Saldivar 2D
Posts: 28
Joined: Fri Sep 25, 2015 3:00 am

### Standard Cell Potential Significant Figures on Midterm

For the recent midterm on question 8 why is there three siginificant answers in the form of 1.20V when the two other cell standard cell potentials of .80V and -.40V only have 2 significant figures?

Bryan Lau 3H
Posts: 53
Joined: Fri Sep 25, 2015 3:00 am

### Re: Standard Cell Potential Significant Figures on Midterm

Because for addition the rules for sig figs are different. You round with respect to the number whose digits place ends furthest to the left. For example, .80 and .40 are both to the hundredths place, so the answer upon addition will be rounded to the hundredths place.

Therefore, the answer is 1.20 and not 1.2

BrandonV
Posts: 6
Joined: Wed Nov 18, 2015 3:00 am

### Re: Standard Cell Potential Significant Figures on Midterm

Because .80V and .40V is the same as 0.80V and 0.40V, which is 3 significant figures

Bryan Lau 3H
Posts: 53
Joined: Fri Sep 25, 2015 3:00 am

### Re: Standard Cell Potential Significant Figures on Midterm

BrandonV wrote:Because .80V and .40V is the same as 0.80V and 0.40V, which is 3 significant figures

Actually, I don't think you should consider the sig figs like this. 0.80V and 0.40V are still 2 sig figs. Rather, you should treat the sig figs like how I mentioned in the previous comment. Rules for sig figs are different when dealing with addition/subtraction, compared to when dealing with multiplication/division.