Rounding/ Significant Figures

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).

Moderators: Chem_Mod, Chem_Admin

Jennifer Su 2L
Posts: 47
Joined: Wed Nov 21, 2018 12:20 am

Rounding/ Significant Figures

Postby Jennifer Su 2L » Tue Jan 15, 2019 10:40 pm

I did not have Lavelle before and was wondering about how we should round our answers. I noticed that the answers in the answer manual for the 6th edition textbook often don't follow the rules of significant figures. For example, let's say there is a given value of 0.385M in the problem. I would assume the answer should have three significant figures too, but the answer in the answer key would round to the tenths place only (ie 0.6M versus 0.587M).

Does anyone know how we should round our answers, and if we would ever be marked down for having a more "accurate" answer?

Jeannine 1I
Posts: 73
Joined: Fri Sep 28, 2018 12:27 am

Re: Rounding/ Significant Figures

Postby Jeannine 1I » Tue Jan 15, 2019 11:05 pm

Remember that when looking at a problem, you use the number with the least amount of sig figs for your answer. So in the problem you're talking about, are you sure there wasn't a number given somewhere that only had 1 significant figure? At least from the problems I've looked at, the solution manual is usually accurate in representing the number of sig figs we're supposed to use(:

Another alternative would be that it's incorrect, and Lavelle has a list of manual errors on his website that you can check!

Jennifer Su 2L
Posts: 47
Joined: Wed Nov 21, 2018 12:20 am

Re: Rounding/ Significant Figures

Postby Jennifer Su 2L » Tue Jan 15, 2019 11:35 pm

I think I counted wrong. I forgot that numbers like 20.0 is only 1 sigfig and not 3. Thank you for your help!

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

Re: Rounding/ Significant Figures

Postby Brianna Brockman 1F » Sun Mar 17, 2019 6:35 pm

Lavelle does count sig figs in the final, but as far as the book, he has a list of book errors on his website.


Return to “General Science Questions”

Who is online

Users browsing this forum: No registered users and 1 guest