What exactly is a Mole?

A mole is:

• a unit of measurement

• based on a reproducible formula (which gives us a consistent method for converting between atoms/molecules and grams.)

• the quantity of anything that has the same number of particles found in 12.000 grams of Carbon-12. (hence the name ‘the chemist’s dozen’)

What does Avogadro have to do with it?

Avogadro came up with the idea that “equal volumes of gases at the same temperature and pressure contain the same number of molecules”

And then that idea was rejected because it did not appear to be consistent with conventionally accepted ideas.

Then the idea of a mole was introduced and the number of molecules in a mole is now called Avogadro’s number because he was the guy who originally conceived of the principle that defines the mole. Well done Avogadro!