## What decimal place to round to when taking masses from the Periodic Table?

Kimberly Bauer 4E
Posts: 51
Joined: Thu Jul 25, 2019 12:17 am

### What decimal place to round to when taking masses from the Periodic Table?

I am aware different periodic tables give different amounts for the atomic mass. Is there a certain decimal place we should round to or should we put in the whole number for the atomic mass and in calculating molar mass?

Karyn How 1J
Posts: 50
Joined: Thu Jul 25, 2019 12:16 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

Hi,

I would just use the entire number that is given from the periodic table, just for extra accuracy. I think it's best to reference the periodic table that's in the textbook since our homework probems are also in there.

Lilyana Villa 1J
Posts: 50
Joined: Sat Aug 17, 2019 12:15 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

My recommendation is 2 to 3 decimal places. I don't think the professor is too strict on the rounding since not rounding at all is super excessive and could leave more room for error when typing it on the calculator to solve a problem.

ASetlur_1G
Posts: 101
Joined: Fri Aug 09, 2019 12:17 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

I would use the entire number and then use sig figs in your final answer.

Alfred Barrion 2H
Posts: 100
Joined: Sat Jul 20, 2019 12:16 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

For more accuracy, you should use all decimal places on the periodic table that is provided. Feel free to round to the amount of sig figs needed at the end of the problem.

Emil Velasco 1H
Posts: 96
Joined: Wed Nov 21, 2018 12:19 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

Personally I use two to three decimal places but I feel like in test, we should use all of the decimals for extra accuracy in our calculation

sbottomley3a
Posts: 50
Joined: Wed Sep 18, 2019 12:19 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

I use all of the decimal places given usually, but I stop at 3 if pressed for time. I think using sig figs at the end is the best way to ensure accuracy in your calculations. But, on the exam we all should be given the same table so any problems from slight differences in masses we see on the homework shouldn't be an issue.

vanessas0123
Posts: 100
Joined: Wed Sep 11, 2019 12:17 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

I usually use the full number the periodic table gives you in all my calculations, then use sig figs for the final answer.

Posts: 104
Joined: Fri Aug 09, 2019 12:16 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

I think the most accurate way to go about taking masses from a periodic table is by taking the entire number that's given on the sheet and using in your calculations. This way you are sure to prevent rounding error and can then use the sig figs from the problem to round later on

Celena Kim 2I
Posts: 106
Joined: Sat Sep 14, 2019 12:17 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

I also usually use the full number given on the periodic table just to be exact as well, but I have noticed some people round their masses from the periodic table to about 2 or 3 decimal places.

Midori Hupfeld 3D
Posts: 55
Joined: Fri Aug 30, 2019 12:17 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

I round at the end, so just take the exact number from the periodic table, which is usually to two decimal places, except for hydrogen- I always use 1.008.

Denise Montes 3B
Posts: 15
Joined: Thu Jul 25, 2019 12:17 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

It's more accurate to use the whole number when doing the actual problem but you should round your answer and used scientific notation if necessary.

Sears 4A
Posts: 36
Joined: Tue Feb 05, 2019 12:15 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

I usually use the entire mass given on the table, so 2 decimal places, and then follow my sig figs from there

Sears 4A
Posts: 36
Joined: Tue Feb 05, 2019 12:15 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

I usually use the entire mass given on the table, so 2 decimal places, and then follow my sig figs from there

Joowon Seo 3A
Posts: 100
Joined: Sat Aug 24, 2019 12:17 am
Been upvoted: 1 time

### Re: What decimal place to round to when taking masses from the Periodic Table?

Atomic numbers are usually carried out to four significant figures such as with hydrogen being 1.008 and carbon being 12.01. So I would just use four significant figures, and it should be fine.

405318478
Posts: 90
Joined: Sat Jul 20, 2019 12:16 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

A student asked Professor Lavelle this same question in lecture on Friday. He said he uses all the decimal places, and waits to round until the final answer.

Kaylee Clarke 1G
Posts: 103
Joined: Fri Aug 30, 2019 12:15 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

I would recommend using the entire number to begin with so you have the most accurate answer and then when you have the solution you can use sig figs to decide where to round.

Omar Selim 1D
Posts: 108
Joined: Sat Jul 20, 2019 12:16 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

Just make sure to stay consistent. I typically always use 2 decimal places and I would recommend not using less but if you wanna use more that's fine too.

rohun2H
Posts: 100
Joined: Wed Sep 18, 2019 12:19 am

### Re: What decimal place to round to when taking masses from the Periodic Table?

I think it is best to use the entire figure given, then round the final answer based on sig figs.