This is not a homework question. It's the beginning of August for pete's sake. I read that like dissolves like, but what about the density of the molecules that are being dissolved? For instance in a solution (gaseous or liquid) of CO2 and CH4, they are both nonpolar, so they mix. However, CO2 is quite a bit more dense. So wouldn't it settle to the bottom? The above situation doesn't make sense to me on why they dissolve in the first place either. I understand how ionic molecules dissolve in a polar substance. For instance, NaCl in H2O. The crystalline substance, NaCl, is more or less picked apart by water molecules due to attraction of opposite charges, but there is a lack of opposite charge attraction in NON polar molecules other than dispersion forces from what I understand. What makes a nonpolar substance dissolve another one? Is this a situation where "It just does?"