Number of sig figs in answer

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mg504733543
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Number of sig figs in answer

Postby mg504733543 » Sun Oct 09, 2016 2:25 pm

Should the sig figs of my final answer match the number of sig figs given?

Ex. If I'm given 2.0 M and 125 mL, should my answer be rounded to 2 sig figs?

Chem_Mod
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Re: Number of sig figs in answer

Postby Chem_Mod » Sun Oct 09, 2016 2:25 pm

Correct, if you're using the 2.0 M value in your calculation.

Katie 1E
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Re: Number of sig figs in answer

Postby Katie 1E » Tue Oct 03, 2017 12:10 pm

However, just because you're using 2 sig figs in your answer, that doesn't necessarily mean that you should use 2 sig figs during your calculations. Two sig figs isn't very precise, so during your calculations you may want to use three or four sig figs, then use only 2 sig figs only when giving your final answer.

jillian1k
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Re: Number of sig figs in answer

Postby jillian1k » Tue Oct 03, 2017 5:06 pm

so just to be clear, it doesn't matter how many sig figs we use at any step in the problem as long as there is the correct amount in the final answer?

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Re: Number of sig figs in answer

Postby Chem_Mod » Tue Oct 03, 2017 9:54 pm

It is important not to use less sig figs at any step in the solution than you have in the actual problem. It is always better to use more along the way and round up at the end.

Jennie Fox 1D
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Re: Number of sig figs in answer

Postby Jennie Fox 1D » Wed Oct 04, 2017 11:47 pm

As long as the significant figures in your answer match the significant figures given in the problem (or whichever number you are using for calculations), you will be fine. You will get a much more accurate answer if you don't round numbers during your calculations. Just make sure that the significant figures given in the problem match the significant figures in your answer!

Alexia Joseph 2B
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Re: Number of sig figs in answer

Postby Alexia Joseph 2B » Thu Oct 05, 2017 12:55 pm

Should we be rounding w/ significant figures in every calculation in a problem or just in our final answer? My TA told me that we should, but I recalled Dr. Lavelle saying that we only needed to acknowledge sig figs in our final answer.

Angel R Morales Dis1G
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Re: Number of sig figs in answer

Postby Angel R Morales Dis1G » Thu Oct 05, 2017 4:10 pm

Hey, I had the same question too, but after asking my T.A and watching several youtube lessons on sig figs, it is always better to have a couple sig figs in your calculations and once you arrive at your final calculation, you round up the significant figures. For instance, if I knew I only needed 3 significant figures, I would do calculations with 3-4 sig figs. If you keep rounding after every step your final answer may not be precise.

Irma Ramos 2I
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Re: Number of sig figs in answer

Postby Irma Ramos 2I » Thu Oct 05, 2017 8:48 pm

Yes, I agree. It's always good to save the rounding and finding the sig figs for the end. Doing it like this allows for the answer to be more accurate.


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