## Molar Mass and Atomic Mass

Yingru_Huang_3E
Posts: 4
Joined: Fri Sep 29, 2017 7:07 am

### Molar Mass and Atomic Mass

So far, I understand the material, but I am just curious conceptually as to why we use the atomic mass on the periodic table, which has its own units (atomic mass units), as molar mass when we solve these problems? Is it because atomic mass units are the same as molar mass units (g.mol^(-1)), and hence can be converted between the two units?

Sean Monji 2B
Posts: 66
Joined: Fri Sep 29, 2017 7:06 am

### Re: Molar Mass and Atomic Mass

I think we use molar mass for conversions because it is the average mass per mole of commonly found isotopes of that element. Atomic mass is specific to one isotope, and is the number of protons and neutrons in that one atom. Basically, molar mass is an average that can be used as a basis for converting between mols and grams while atomic mass is just a measurement of protons and neutrons.

They use the wrong terminology for molar mass on the periodic table most times, calling it atomic mass, though it is really the molar mass since no element has one specific mass. I think they do this so it’s easier to understand for teaching purposes.

The units are a result what is being measured or what the numbers represent, not just for conversion purposes. They are, though, helpful for checking if a conversion is correct (as Professor Lavelle has said)

Melissa_Aguirre1J
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Joined: Tue Nov 14, 2017 3:02 am

### Re: Molar Mass and Atomic Mass

The molar mass is the atomic mass expressed in grams.

Chem_Mod
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### Re: Molar Mass and Atomic Mass

The molar mass is the mass of 1 mole of the compound. It is not the atomic mass expressed in grams.