Significant Figures for Calculations with Molar Masses

Moderators: Chem_Mod, Chem_Admin

Ria Nawathe 1C
Posts: 103
Joined: Wed Sep 30, 2020 9:39 pm
Been upvoted: 3 times

Significant Figures for Calculations with Molar Masses

Postby Ria Nawathe 1C » Mon Oct 05, 2020 10:16 am

Are molar masses considered measured values or defined constants?

Jessica Katz
Posts: 111
Joined: Wed Sep 30, 2020 10:09 pm
Been upvoted: 2 times

Re: Significant Figures for Calculations with Molar Masses

Postby Jessica Katz » Mon Oct 05, 2020 10:18 am

The molar masses are defined constants so they do not affect the significant figures that need to be included in your answer. I think it's because every periodic table could have the molar masses rounded to a different number and because they are the same in every single problem so they don't influence your final answer.

Aydin Karatas 1F
Posts: 119
Joined: Wed Sep 30, 2020 9:37 pm

Re: Significant Figures for Calculations with Molar Masses

Postby Aydin Karatas 1F » Mon Oct 05, 2020 10:34 am

You can consider them as constants because they are known values. Sig figs will be determined from other non-constant, values given in a problem.

Nika Gladkov 1A
Posts: 122
Joined: Wed Sep 30, 2020 9:33 pm
Been upvoted: 6 times

Re: Significant Figures for Calculations with Molar Masses

Postby Nika Gladkov 1A » Mon Oct 05, 2020 10:38 am

To add on to the previous replies, molar masses could also be adjusted to the level of accuracy that you need so that they don't interfere with calculations. If the source that you are using doesn't have the correct number of significant figures, and you think that it is a significant issue, you could try to find another source that gives more significant figures.

Crystal Yu 1D
Posts: 167
Joined: Wed Sep 30, 2020 9:58 pm
Been upvoted: 12 times

Re: Significant Figures for Calculations with Molar Masses

Postby Crystal Yu 1D » Mon Oct 05, 2020 11:30 am

Molar masses are defined constants.

For me, the easiest way to determine how many sig figs I should be using in my answer is by looking back at the problem and the given values. Generally the values given in the questions are the ones that you will begin your calculations with. The given values are then adjusted using defined constants, ratios of moles, etc as you solve the problem.

I'm not sure if my phrasing was the best, but I hope this makes sense!

Kaiya_PT_1H
Posts: 87
Joined: Wed Sep 30, 2020 10:07 pm

Re: Significant Figures for Calculations with Molar Masses

Postby Kaiya_PT_1H » Thu Oct 08, 2020 12:22 pm

Nika Gladkov 3b wrote:To add on to the previous replies, molar masses could also be adjusted to the level of accuracy that you need so that they don't interfere with calculations. If the source that you are using doesn't have the correct number of significant figures, and you think that it is a significant issue, you could try to find another source that gives more significant figures.


Would it be better to adjust the molar mass to match the significant figures rest of the numbers in the problem, or would that make the result less accurate?


Return to “Significant Figures”

Who is online

Users browsing this forum: No registered users and 1 guest