Chemistry - Moles

Moles, they are a unit of measurement.  Moles are a representative particle.
Avogadro's Number, or Avogadro's Constant. 
It is equal to =  6.02 × 10²³

For more help, there is a song to remember it called 'A Mole Is A Unit'.

If you have a mass of a substance, you can convert it to moles by multiplying it by 1mole over the molar mass (g), or 1mole/molar mass(g).

If you have the volume of a substance, you can convert it to moles by multiplying it by 1mole over 22.4 litres (L), or 1mole/22.4L.  Note, this is assuming that it is in STP (Standard Temperature and Pressure).

If you have the amount of representative particles, example atoms, molecules, ions, etc. you would take the amount and multiply it by 1mole over avagadro's number, or 1 mole over 6.02x10^23. 

Once you convert anything to moles, you can convert to Mass (g), Representative Particles (atoms, etc.) or Volume (L). 

Here is a Y Chart to help with the conversions.

Here is an example going from grams (mass) to molecules (representative particles).
The question is: How many molecules are there in 450 grams of Na₂SO₄ ?

* Notes, remember significant figures and units!
* Moles are used a lot in chemistry, and chemistry related topics!
*Good luck!