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### Molar Mass

Posted: 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?

### Re: Molar Mass

Posted: Sun Oct 06, 2019 2:28 pm
A periodic table will probably be provided

### Re: Molar Mass

Posted: 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.

### Re: Molar Mass

Posted: 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.

### Re: Molar Mass

Posted: 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.