November 14th - How Many Moles Am I?

Yes! We will find out my mass in moles in this blog. But moles have different masses, known as molar masses. A molar mass is defined as the mass in grams of one mole of a substance.

It can be determined from the atomic mass on the periodic table. It is measured in grams/mol.

Example! Let's use the element oxygen. Referring to the periodic table: 16.0 amu. What does amu stand for? Well, it's the abbreviation for atomic mass units. 16.0 amu is the mass of one element of oxygen. amu is based on 1/12th of the mass of an atom of carbon-12. Therefore, the mass of carbon-12 is exactly 12 amu.

Another important thing to remember is diatomic molecules! Oxygen, fluorine, and chlorine are examples. When alone these elements exist in pairs, so be careful and remember an oxygen molecule actually refers to two oxygen atoms.

How much of a mass is that? Well, since one oxygen is 16.0 amu, then two will have a mass of 32.0 amu.

The amu corresponds directly to the molar mass. To convert, we simply take the amu and change it to grams per mole. It's as easy as that! In chemistry, we prefer this because it is extremely hard to work with one or two atoms. This is where the mole, which expresses a very large quality, helps us in conversions.

Let us use the element tungsten. This element, since it contains its relative abundance of isotopes, has a molar mass of: 183.8 grams per mole.

The conversion from grams to mole is explained in the post above.

I have a mass equivalent to that of 337.32 moles of W. If you are curious to find out how much this is, we suggest you refer to the upcoming post. This will teach you about conversions between grams and moles.

Posted by Andrew.