What is the difference between mole and molecule?

1 Answer
Jan 3, 2016

A molecule, for example of water, contains 2 hydrogen atoms and 1 oxygen atom chemically bounded together and is the smallest building block of the chemical water. The molecules are then held together by intermolecular forces, in this case by strong hydrogen bonds.

A mole is a certain quantity of molecules, namely the Avagadro number of molecules #N_A=6.023xx10^23#.
So for example if you take #6.023xx10^23# water molecules then that makes up 1 mole of water.
Its mass would be the molar mass of water, meaning that 1 mole of water with that large number of particles has a mass of #M_r=1+1+16=18g//mol#.

By definition, 1 mole is said to be the number of particles contained in 12g of the carbon-12 isotope.