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Sig Figs

Posted: Wed Oct 04, 2017 9:50 am
by Mitch Mologne 1A
When doing a problem that does not have any number values in the question but uses molar masses that extend to 4 sig figs, should you use the standard 3 sig figs in your answer or 4 sig figs coming from the molar masses?

Re: Sig Figs

Posted: Wed Oct 04, 2017 11:50 pm
by Emma Boyles 1L
Even though the molar masses may have 4 sigfigs, I think you only need 3 sigfigs in your final answer. Hope that helps!

Re: Sig Figs

Posted: Wed Oct 04, 2017 11:52 pm
by aTirumalai-1I
If no values are specified in the problem, I would use the molar masses and round to 4 sig figs, since the periodic table allows for that precision. AKA whenever possible, it's best to be more precise.

Re: Sig Figs

Posted: Thu Oct 05, 2017 10:44 am
by Brandon Fujii 1K
In addition, if we have to convert our calculated number of moles into grams, do not round off the number of moles. We only round to our number of significant figures at the very end of the problem. i.e. Say we are limited to 3 sig figs, and we calculated 3.45654 moles of Oxygen gas. We would multiply 3.45654 moles of Oxygen by 16.00 g/mol O2 to get 55.3g O2. DO NOT round the number of moles and multiply 3.46 moles of Oxygen by 16.00 g/mol O2. If we rounded the number of moles we would get 55.4g O2. This is known as round off error.

Re: Sig Figs

Posted: Thu Oct 05, 2017 1:14 pm
by Mary Becerra 2D
Personally, I would try to let the calculator do all the work and then round at the very end, so you get the most accurate answer possible.

Re: Sig Figs

Posted: Mon Jun 11, 2018 9:26 pm
by AlyssaRivera
throughout the problem, how many sig figs should we use when plugging things into our calculator? I've gotten different answers on some problems by rounding things that I plug in

Re: Sig Figs

Posted: Tue Jun 12, 2018 12:43 am
by Nandhini_2K
I round my final solution to keep my answer most accurate as possible.

Re: Sig Figs

Posted: Tue Jun 12, 2018 2:21 am
by Jacob Samuels 1E
When in the middle of the problem, you should keep as many decimal places as possible, so that there is no rounding error. I usually keep 3 or 4 more decimals than I will need for my answer, just to be safe.

Re: Sig Figs

Posted: Wed Oct 03, 2018 7:45 pm
by Diana Chavez-Carrillo 3J
How can you check if your sig. figs. are too precise or not rounded off enough?

Re: Sig Figs

Posted: Fri Oct 05, 2018 11:30 am
by 905096106
I would round on your last step because the more you round the more your answer becomes inaccurate.