Week 7:    So, unfortunately Avogadro never got any credit in his lifetime for having the radical thought to make a clear distinction between atoms and molecules. Poor guy.  This is a good website for explaining things about the scientific process..... A good definition of a HYPOTHESIS: merely a tentative explanation of observed events, not a prediction, but it allows you to make predictions that can be tested by experiments (and may eventually become accepted as scientific theory).  Avogadro's number (6.02 x 10 to the 23rd, ) is the number of fundamental particles in a mole of substance.  Gram molecular weight is a convenient weight..... a gram molecular weight of any substance contains (Avogadro's number) of molecules.....a particular volume of gas is proportional to molecular weight.  A MOLE is a gram molecular weight of a gas (at standard temp. and pressure), it occupies 22.4 liters of volume. Another way to say it is: 22.4 liters of a gas (at standard temp and pressure) contain the number of molecules that weigh as much as the molecular weight of the gas expressed in grams.

I think these were good websites..... I would need to hammer it into my brain a lot longer to make it stick though.