Does molar mass count for sig figs?

Moderators: Chem_Mod, Chem_Admin

Sukanya Mohapatra 2G
Posts: 85
Joined: Sat Aug 17, 2019 12:18 am
Been upvoted: 1 time

Does molar mass count for sig figs?

Postby Sukanya Mohapatra 2G » Thu Oct 03, 2019 12:44 am

Do the values of the molar masses we use for calculations affect the number of significant figures the answer contains?

Jonathan Gong 2H
Posts: 89
Joined: Sat Jul 20, 2019 12:16 am

Re: Does molar mass count for sig figs?

Postby Jonathan Gong 2H » Thu Oct 03, 2019 12:47 am

No, only the given values determine the number of sig figs the answer will ultimately have.

Emily Chirila 2E
Posts: 96
Joined: Sat Jul 20, 2019 12:16 am

Re: Does molar mass count for sig figs?

Postby Emily Chirila 2E » Thu Oct 03, 2019 12:50 am

I would keep the molar masses as precise as possible until you get your final calculation to prevent any rounding error. Then, determine the number of sig figs based on the smallest value given in the problem.

Jasmine 2C
Posts: 150
Joined: Wed Sep 18, 2019 12:18 am

Re: Does molar mass count for sig figs?

Postby Jasmine 2C » Thu Oct 03, 2019 12:54 am

It doesn't count for sig figs but I think Dr. Lavelle just likes to round it off (round 15.999 g/mol for O to 16) for lecture to make things simple. But definitely when doing calculations, try to keep all numbers and round off until the end.

Manav Govil 1B
Posts: 89
Joined: Sat Sep 07, 2019 12:19 am

Re: Does molar mass count for sig figs?

Postby Manav Govil 1B » Thu Oct 03, 2019 2:13 pm

The molar mass from the periodic table does not affect our calculations, but the molar mass we get from a question or from our calculations do affect our calculations.

Betania Hernandez 2E
Posts: 90
Joined: Fri Aug 02, 2019 12:15 am

Re: Does molar mass count for sig figs?

Postby Betania Hernandez 2E » Thu Oct 03, 2019 3:14 pm

Is there a certain periodic table that we need to use because I know that some periodic tables online the molar masses are rounded while the one in the textbook is more precise. Would the rounding affect any answers?

Giselle Littleton 1F
Posts: 60
Joined: Wed Sep 18, 2019 12:20 am

Re: Does molar mass count for sig figs?

Postby Giselle Littleton 1F » Thu Oct 03, 2019 4:51 pm

It's your final answer to a problem that counts for sig figs. However, to ensure that your final answer is accurate, I would keep the molar mass and other calculations in between in their longest form as evident on the periodic table and then use sig figs for your final answer.


Return to “Significant Figures”

Who is online

Users browsing this forum: No registered users and 1 guest