## When are sig figs applied?

Linette Choi 3L
Posts: 60
Joined: Wed Sep 30, 2020 9:51 pm

### When are sig figs applied?

When doing a multi-step problem, do we keep calculating the number of significant figures as we complete each step, or we do calculate the number of sig figs at the very end of the problem?

Claire_Kim_2F
Posts: 67
Joined: Wed Sep 30, 2020 10:02 pm

### Re: When are sig figs applied?

I do the sig figs at the end of the problem in order to keep it accurate.

Katie Le 3K
Posts: 62
Joined: Wed Sep 30, 2020 9:35 pm

### Re: When are sig figs applied?

I use sig figs at the end of a multistep equation. I think it's supposed to help with the accuracy of your final answer.

Samuel Flores 1E
Posts: 65
Joined: Wed Sep 30, 2020 9:51 pm

### Re: When are sig figs applied?

I would recommend implementing sig figs for the final answer. While it's possible to make sure the number of sig figs are correct in each step of the problem, ultimately the final answer should have the proper amount of significant figures.
In other words, feel free to do sig figs in each step of the problem, but really the most important step to maintain sig figs in the final answer.

Hope this helps!

Brianna Chen 3F
Posts: 64
Joined: Wed Sep 30, 2020 10:11 pm

### Re: When are sig figs applied?

In this case, should we not round any answers in a multi-step problem until we reach the final answer where we apply the sig fig rule? Also, do you typically round the molar mass of an element from the periodic table? So far, I have been using 1.007 for Hydrogen, 15.999 for Oxygen, etc...but is this too excessive/exact? Should we just round to 1.01 for Hydrogen and 16.00 for Oxygen (this is what I commonly notice)?

Jaclyn Dang 3B
Posts: 72
Joined: Wed Sep 30, 2020 10:02 pm

### Re: When are sig figs applied?

Brianna Chen 1I wrote:In this case, should we not round any answers in a multi-step problem until we reach the final answer where we apply the sig fig rule? Also, do you typically round the molar mass of an element from the periodic table? So far, I have been using 1.007 for Hydrogen, 15.999 for Oxygen, etc...but is this too excessive/exact? Should we just round to 1.01 for Hydrogen and 16.00 for Oxygen (this is what I commonly notice)?

I typically use the actual molar mass and then worry about the sig figs at the end. I also avoid rounding until absolutely necessary to keep the accuracy of my answers.

Brianna Chen 3F
Posts: 64
Joined: Wed Sep 30, 2020 10:11 pm

### Re: When are sig figs applied?

Jaclyn Dang 3A wrote:
Brianna Chen 1I wrote:In this case, should we not round any answers in a multi-step problem until we reach the final answer where we apply the sig fig rule? Also, do you typically round the molar mass of an element from the periodic table? So far, I have been using 1.007 for Hydrogen, 15.999 for Oxygen, etc...but is this too excessive/exact? Should we just round to 1.01 for Hydrogen and 16.00 for Oxygen (this is what I commonly notice)?

I typically use the actual molar mass and then worry about the sig figs at the end. I also avoid rounding until absolutely necessary to keep the accuracy of my answers.

Okay! Definitely. If you do wait until the end, do you still utilize the sig fig rule for multiplication/division and addition in the middle of a problem? Since if a step asked you to add 44.323 and 20.34, would your answer be 64.663 or 66.66 (if this was not the final answer)?

Nick Saeedi 1I
Posts: 71
Joined: Wed Sep 30, 2020 9:39 pm

### Re: When are sig figs applied?

I was taught not to round until the end of a problem so I just apply sig figs when I am done solving.

simona_krasnegor_1C
Posts: 50
Joined: Wed Sep 30, 2020 9:35 pm

### Re: When are sig figs applied?

I agree with what others are saying above; I usually do not take sig figs into consideration until the very end of the problem in order to be as accurate as possible!

George Cazares 1E
Posts: 51
Joined: Wed Sep 30, 2020 9:39 pm
Been upvoted: 1 time

### Re: When are sig figs applied?

In the Chem 14A website in the more sig fig discussion page, it says "you should only round your final answer (see the caution below in the next section), but you will need to keep track of the sig figs carried through each step of the calculation if you want to get to the correct answer."

FionaHunter21
Posts: 60
Joined: Wed Sep 30, 2020 9:37 pm

### Re: When are sig figs applied?

I agree with all of these! I've always done it at the end, as long as you note at the beginning what number of sig figs you should round to at the end. I find it easier to do that when I first read the problem so that I don't get confused later on.

Jeffrey Fenn 1G
Posts: 53
Joined: Wed Sep 30, 2020 10:08 pm

### Re: When are sig figs applied?

Even though I haven't taken chemistry yet, I found when I took physics it was really helpful to keep the sig figs consistent throughout the entire problem to prevent confusion.

Ethan Laureano 3H
Posts: 62
Joined: Wed Sep 30, 2020 9:58 pm

### Re: When are sig figs applied?

As everyone has stated above, round sig figs at the very end. This way, you prevent any inaccuracy by rounding per step. It may seem tedious to write out the full number every step, but it is needed to ensure accuracy.