Molar Mass

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Yazmin Bocanegra 3L
Posts: 51
Joined: Thu Jul 25, 2019 12:17 am

Molar Mass

Postby Yazmin Bocanegra 3L » Sun Oct 06, 2019 2:26 pm

Will we need to have the molar masses of different elements memorized for the tests? If so, how many significant figures should we have down? If not, how do you calculate the molar masses?

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

Re: Molar Mass

Postby Omar Selim 1D » Sun Oct 06, 2019 2:28 pm

A periodic table will probably be provided

Haley Pham 4I
Posts: 51
Joined: Fri Aug 09, 2019 12:16 am

Re: Molar Mass

Postby Haley Pham 4I » Sun Oct 06, 2019 5:27 pm

You do not need to memorize the molar masses of all the elements. A periodic table will be provided. Sometimes molar masses of compounds will be given in the problem, but if not, you would have to use the periodic table to calculate the molar mass.

Rebekah Alfred 1J
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am
Been upvoted: 1 time

Re: Molar Mass

Postby Rebekah Alfred 1J » Sun Oct 06, 2019 5:58 pm

Here's an example of how to calculate molar mass:

Let's say you need to find the molar mass of NaCl. This can be done by adding the atomic mass of sodium (22.99 g/mol) and the atomic mass of chlorine (35.45 g/mol).

(22.99 g/mol) + (35.45g/mol)= 58.44 g/mol

Therefore, the molar mass of NaCl will be 58.44 g/mol.

Mallika Chimpiri 3K
Posts: 58
Joined: Thu Jul 25, 2019 12:17 am

Re: Molar Mass

Postby Mallika Chimpiri 3K » Sun Oct 06, 2019 7:35 pm

You won't have to memorize the molar masses from the periodic table but if the molar mass of a compound or element isn't given in the problem, you should be able to use the periodic table in order to calculate its molar mass. Usually, the molar mass is given and calculated with 4 significant figures.


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