Sig figs confusion

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Doris Cho 1D
Posts: 53
Joined: Thu Jul 11, 2019 12:16 am

Sig figs confusion

Postby Doris Cho 1D » Tue Oct 01, 2019 12:41 pm

I'm having trouble determining how many sig figs should be in my final answer and there aren't any numbers in the problem to tell me the least amount of sig figs to use.
For example, in F5, I rounded the percentages to 4 sig figs but the answers have either 4 or 5 sig figs... is it just a trial and error thing where I see which numbers will add up to 100%?

Shivam Rana 1D
Posts: 106
Joined: Fri Aug 09, 2019 12:16 am

Re: Sig figs confusion

Postby Shivam Rana 1D » Tue Oct 01, 2019 12:50 pm

I also didn't know how many sigfigs to use; I went with 4 though. I think the more important thing is to make sure that the individual percentages add up to 100%. I'd also look at the number of figures on the periodic table you're using, but I'm not totally sure that is the correct way to determine the number of sigfigs that need to be present.

Verity Lai 2K
Posts: 100
Joined: Sat Aug 24, 2019 12:18 am

Re: Sig figs confusion

Postby Verity Lai 2K » Tue Oct 01, 2019 12:57 pm

I usually use three sig figs if I'm not given any numbers to base the sig figs on, but the more sig figs you use, the more acurate your values are generally going to be.

Clara Cho 2K
Posts: 103
Joined: Wed Sep 18, 2019 12:18 am

Re: Sig figs confusion

Postby Clara Cho 2K » Tue Oct 01, 2019 4:58 pm

I also was confused by F5 I started with 3 sig figs, but the answer key had 4 or 5. Which one should I go with?

Donavin Collins 1F
Posts: 66
Joined: Sat Sep 14, 2019 12:16 am

Re: Sig figs confusion

Postby Donavin Collins 1F » Tue Oct 01, 2019 5:45 pm

Can someone briefly explain sig figs? My current understanding is that it's when you round to a certain place (tenth, hundredth...), but this is a topic that I never really understood. Also, is there is certain area of chemistry where you use it frequently? Thanks.

Katherine Brenner 3H
Posts: 73
Joined: Wed Sep 18, 2019 12:18 am

Re: Sig figs confusion

Postby Katherine Brenner 3H » Tue Oct 01, 2019 6:10 pm

Hello

I am having the same problem- Im never really sure how many sig figs to use in each question. I normally just use the amount that they give inside the question (if they give a specific number).

Subashni Rajiv 1K
Posts: 101
Joined: Wed Sep 18, 2019 12:16 am

Re: Sig figs confusion

Postby Subashni Rajiv 1K » Tue Oct 01, 2019 6:17 pm

Your answer should have the same number of sig figs as the given value with the smallest number of sig figs.

Minh Ngo 4G
Posts: 137
Joined: Thu Jul 25, 2019 12:17 am

Re: Sig figs confusion

Postby Minh Ngo 4G » Tue Oct 01, 2019 6:36 pm

If they give you a number in the problem, usually you would then round your answer to the sig figs of that number. If not, i think the sweet spot is 3

Sion Hwang 4D
Posts: 51
Joined: Wed Sep 18, 2019 12:21 am

Re: Sig figs confusion

Postby Sion Hwang 4D » Thu Oct 03, 2019 1:10 am

Your final answer cannot be more precise than the measurements taken and given.
Generally, however, if the problem does not specifically indicate any measurement with significant figures, I would go with two numbers after the decimal (i.e. 35.45 or 2.15).


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