On Thu, 27 May 2004 14:31:54 +0200, "Reka"
wrote:

Yes, but *which* of the three are smaller and how can I tell that from the
formula?
--

In this case, fewer atoms equals smaller molecule.

Isopropanol is C3H8O - 3 carbon atoms, 8 hydrogen, 1 oxygen
Ethanol is C2H6O - 2 carbon atoms, 6 hydrogen, 1 oxygen
Methanol CH4O - 1 carbon atoms, 4 hydrogen, 1 oxygen

deg