Sig Figs

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805377003
Posts: 102
Joined: Wed Sep 30, 2020 10:10 pm

Sig Figs

Postby 805377003 » Sun Oct 11, 2020 11:38 am

Can someone explain Sig Figs?

705340227
Posts: 91
Joined: Wed Sep 30, 2020 10:08 pm

Re: Sig Figs

Postby 705340227 » Sun Oct 11, 2020 11:43 am

Hey!

When doing sig figs, you have to follow a set of rules to determine how many sigs figs a number has.

For a number such as 43, there are two sig figs. 122 has three and 9 has one.
When a number without a decimal has zeroes after it, you do not count the zeroes as part of the number of sig figs. For example, 6200 has two sig figs and 9810 has three.
When there is a decimal, the zeroes count in the above situations. For example, 6200. would actually have four sig figs and 9810. has four.
Zeroes after the decimal place count if there is a number before the decimal. For example, 540.00 has five sig figs and 1.000 has four.
Zeroes before numbers but after the decimal do not count. For example, 0.001 has one sig fig and 0.0120 has three.

Hope this helps!

605291562
Posts: 91
Joined: Wed Sep 30, 2020 10:07 pm

Re: Sig Figs

Postby 605291562 » Sun Oct 11, 2020 4:10 pm

Hi! Sig Figs are used to make sure we are accurately presenting how precise the data we used is. For example if we measured something with a beaker that only had dashes for every 10 cm we could not be as precise as if we were measuring with something that has dashes at every cm. sig figs takes this into account and allows us to truthfully report data.

Kaitlyn Hernandez 3I
Posts: 133
Joined: Wed Sep 30, 2020 9:37 pm
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Re: Sig Figs

Postby Kaitlyn Hernandez 3I » Sun Oct 11, 2020 4:41 pm

Hi!

A simple technique that I use when counting Sig Figs is the Pacific Atlantic Rule, which I learned in high school chemistry. If a decimal place is Present, you'll start counting sig figs (beginning with the first non-zero digit) from the left or the "Pacific" side. For example, the number 120340.0 has 7 sig figs (1 2 0 3 4 0 0). If a decimal place is Absent, you'll start counting sig figs (beginning with the first non-zero digit) from the right or "Atlantic" side. For example, the number 120340 has 5 sig figs (1 2 0 3 4).

I hope this helps :)

This is also a helpful link from Lavelle's website if you need extra help:
https://lavelle.chem.ucla.edu/wp-conten ... ussion.pdf

Carolina Gomez 2G
Posts: 90
Joined: Wed Sep 30, 2020 9:32 pm

Re: Sig Figs

Postby Carolina Gomez 2G » Sun Oct 11, 2020 8:41 pm

The following notes helped me better understand how many sig figs are in a number/ how many sig figs a number should have after a calculation. Hope this helps!

#1: All numbers 1-9 are significant. Ex: 1 (1 sig fig) , 3.5 (2 sig figs)
#2 "Leading Zeros" are never significant. Ex: 0.11 (2 sig figs) , 0.0003 (1 sig fig)
#3 "Sandwich Zeros" are significant. Ex: 2006 (4 sig figs), 1.00404 (6 sig figs)
#4 "Trailing Zeros" are only significant if there is a decimal point. Ex: 10.0 (3 sig figs) , 150 (2 sig figs)

Calculations with significant figures
For addition and subtraction: limit and round to the least number of decimal places.
For multiplication and division: limit and round to the least total number of sig figs.


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