## Basic Sig Figs

Thomas_Elizabeth_3A
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Joined: Wed Sep 21, 2016 2:57 pm

### Basic Sig Figs

In my high school chemistry class, we never learned sig figs so I was going to see if anyone could give me a basic overview of what they are and how they work? Thanks!

Chem_Mod
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### Re: Basic Sig Figs

If you turn to page 26 of the course reader, there is an excellent guide to sig figs

SarahTian3k
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### Re: Basic Sig Figs

There's a helpful way to remember how to find sig figs called the Atlantic Pacific Rule. In the A(tlantic)bsence of a period, you discount all the 0s to the right of the nonzero number(the Atlantic Ocean is to the right of America). If there is a P(acific)eriod, you ignore all the 0s to the left of the nonzero number(the Pacific Ocean is to the left of America).

JulissaLopez1F
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### Re: Basic Sig Figs

I don't understand why trailing zeros are not counted as sig figs.. can someone explain?

veeksha25
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Joined: Wed Sep 21, 2016 2:56 pm

### Re: Basic Sig Figs

Trailing zeros, as well as leading zeros, both don't count as significant figures because they are simply placeholders in the number. However, if there is a decimal, then the zeros do count as significant. For example, 400 has only one significant figure because the zeros are just placeholders; but 400. has three significant figures because the zeros are followed by a decimal.

CameronJohari1J
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### Re: Basic Sig Figs

If you are still confused, the link "Everything you want to know about Sig Fig" on Dr. Lavelle's website is extremely helpful. Another resource would be the appendix section 1C for the 6th edition of the textbook which covers sig figs in depth.

605011646
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### Re: Basic Sig Figs

and zeros trapped between natural numbers count too

Sonja Kobayashi 1H
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### Re: Basic Sig Figs

For significant figures it depends on if there is a decimal point. If there is a decimal point, then you go to the left most non-zero digit of the number of count the amount of digits to the right of that first non-zero number. For example 0.0500 would have three sig figs because five is the first non-zero number and then there are two more numbers following the 5. If there is not a decimal point, you start from the right side and go left and count the digits starting from the first non-zero number. For an example 14,790 has four sig figs! I hope that helped!

kendallbottrell
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### Re: Basic Sig Figs

Is maintaining significant figures necessary in this class? I can't remember if he mentioned it. If so, I would need a refresher..

Christina Inchuachan 1C
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Joined: Wed Nov 15, 2017 3:04 am

### Re: Basic Sig Figs

I think he said we don't have to worry as much about significant figures right now, but you should still understand it. Basically, when you add something you save the large number of decimal points. When you multiply something, you save the lowest number of figures.

Jacob Samuels 1E
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### Re: Basic Sig Figs

I know that we don't need to worry about sig figs for this week's test, but do you all think we will need them for the next test?

JooHyun Koh 1H
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Joined: Fri Apr 06, 2018 11:03 am

### Re: Basic Sig Figs

I know that sig figs aren't that important this test, but I think it'd be helpful to make it a habit of writing the answer in the right sig figs (my TA said that sig figs only matter for the answer and not in the actual process) since it might be useful later in the course or maybe in other courses

Gabi Landes 1-H
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### Re: Basic Sig Figs

When you get the final answer for a problem, for example,

#2. CHEM, an FM radio station, broadcasts at 99.5 MHz. What is the wavelength of the corresponding radio waves?" (from TA worksheet 2)

would the resulting answer have be rounded to 3 sig figs because of the "99.5 MHz"?

AnnaYan_1l
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### Re: Basic Sig Figs

Gabi Landes 1-H wrote:When you get the final answer for a problem, for example,

#2. CHEM, an FM radio station, broadcasts at 99.5 MHz. What is the wavelength of the corresponding radio waves?" (from TA worksheet 2)

would the resulting answer have be rounded to 3 sig figs because of the "99.5 MHz"?

Yes, 3 sig figs would be appropriate here.