Sig figs

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Quynh Vo
Posts: 45
Joined: Sun Sep 29, 2019 12:15 am

Sig figs

Postby Quynh Vo » Sat Oct 05, 2019 5:09 pm

How come some numbers have a .0 at the end in questions? For example, it is 30.0 g instead of just 30 g.

Jacob Motawakel
Posts: 72
Joined: Wed Sep 18, 2019 12:20 am
Been upvoted: 1 time

Re: Sig figs

Postby Jacob Motawakel » Sat Oct 05, 2019 5:14 pm

It is a different amount of sig figs. 30 g has one sig fig, and 30.0 g has three sig figs.
Last edited by Jacob Motawakel on Sat Oct 05, 2019 5:16 pm, edited 1 time in total.

Bao Tram Nguyen
Posts: 35
Joined: Sat Aug 24, 2019 12:17 am

Re: Sig figs

Postby Bao Tram Nguyen » Sat Oct 05, 2019 5:14 pm

What a good question! This is where significant figures come into play. When you write 30 g, you are only allowed to use 2 significant figures to answer the question versus 30.0 g which allows you to write 3 sig figs. Also writing 30.0 g makes the measurement more precise and shows you that it is exactly 30.0 g instead of 30.4 g or something like that. It is important to be as precise as possible especially when it comes to very small numbers.

Amanda Mei 1B
Posts: 93
Joined: Sat Aug 24, 2019 12:16 am

Re: Sig figs

Postby Amanda Mei 1B » Sat Oct 05, 2019 5:26 pm

30 is just one sig fig, 30. would be two, and 30.0 would be three. A decimal indicates the tailing zeroes to be significant (e.g. 30. or 30.0). You can also use scientific notation to make sure sig figs are correct. You should check out Lavelle's "Everything you want to know about Sig Fig" file under Course Materials.

Viviana Velasquez
Posts: 86
Joined: Sat Jul 20, 2019 12:15 am

Re: Sig figs

Postby Viviana Velasquez » Sun Oct 06, 2019 7:53 pm

That .0 makes the difference between only using one sig fig and using 3 sig figs.

Kendra Barreras 3E
Posts: 51
Joined: Mon Sep 23, 2019 12:16 am

Re: Sig figs

Postby Kendra Barreras 3E » Sun Oct 06, 2019 8:19 pm

It basically is just telling you that there are 3 sig figs and given that that is your least number of sig figs in the problem, that amount would be the one you would use for your answer.

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