Significant figures  [ENDORSED]

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Alondra Cervantes 1F
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Significant figures

Postby Alondra Cervantes 1F » Sun Jun 26, 2016 12:52 pm

Can someone please further explain how many significant figures to use when writing an answer. I am still a bit confused.

Chem_Mod
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Re: Significant figures  [ENDORSED]

Postby Chem_Mod » Sun Jun 26, 2016 1:47 pm

plz refer to the following doc to check what you need to know about sigfig
https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/EVERYTHING_YOU_WANTED_TO_KNOW_ABOUT_SF.pdf

Alondra Loera 1A
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Re: Significant figures

Postby Alondra Loera 1A » Sun Jun 26, 2016 9:29 pm

Significant figures are the number of digits in an answer relative to the numbers in the problem.

11.2 has 3 significant figures
11.20 has 4 significant figures
0.011 has 2 significant figures

with decimals, the significant figures are counted after the first integer so for 0.011, 1 and anything after counts as a sig. fig.

This Khan Academy video is very helpful as well https://www.khanacademy.org/math/pre-algebra/decimals-pre-alg/sig-figs-pre-alg/v/significant-figures

Sara Juarez 1B
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Re: Significant figures

Postby Sara Juarez 1B » Sun Jun 26, 2016 10:14 pm

The number of significant figures will depend on the problem. If I am not mistaken, I believe you look to your original problem and look for the number that has the smallest significant figure and go off of that. Significant figures don't take into account leading 0's. So 0.1 and 0.000001 are both 1 sig fig. However trailing 0's are significant. 0.0102 is 3 sign figures because the first non zero number starts with 1 and than it is followed by two additional numbers.

EmmaSkeie 1F
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Joined: Fri Jun 17, 2016 11:28 am

Re: Significant figures

Postby EmmaSkeie 1F » Wed Jun 29, 2016 2:21 pm

Hi,

For quiz 1: If we are given a problem that has 3 different values, each of different number of significant figures (say the least number of SF is 2), do we round off the other numbers to 2 SF for every step, or do we keep the values given and then round off the answer to SF at the very end?

Thank you!

Chem_Mod
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Re: Significant figures

Postby Chem_Mod » Wed Jun 29, 2016 2:48 pm

The rules for rounding are also described in the link of the endorsed post.

Rob_Carter_1L
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Trailing zeroes

Postby Rob_Carter_1L » Sun Sep 25, 2016 11:13 am

Just confirming, I know that 0.0100 would have 3 sigfigs due to trailing zeros, but would 1.00 have 3 as well? Is it the same after decimal points?

Kathy Vu 3L
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Joined: Fri Jul 15, 2016 3:00 am

Re: Trailing zeroes

Postby Kathy Vu 3L » Sun Sep 25, 2016 12:05 pm

Rob_Carter_1L wrote:Just confirming, I know that 0.0100 would have 3 sigfigs due to trailing zeros, but would 1.00 have 3 as well? Is it the same after decimal points?


Yes, 1.00 would have 3 significant figures as well since the 2 zeros are trailing zeros behind a decimal point

Kathy Vu 3L
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Joined: Fri Jul 15, 2016 3:00 am

Re: Significant figures

Postby Kathy Vu 3L » Sun Sep 25, 2016 12:12 pm

Is there usually a range of answers we can put on quizzes and exams, or is there only 1 answer that is allowed?

For example what if my answer is 2.5, but others got 2.6 due to a different amount of decimals used during calculations

Chem_Mod
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Re: Significant figures

Postby Chem_Mod » Sun Sep 25, 2016 11:00 pm

I provide all students with the same constants, equations, and periodic table.
Therefore all students should have the same answer if sig-fig and round-off are done correctly.


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