CHEMISTRY
posted by werwer on .
What do we assume about the volume of the actual molecules themselves in a sample of gas, compared to the bulk volume of the gas overall? Why?

One of the assumptions made in the Kinetic Molecular Theory is that the molecules have zero volume. Neglecting the volume term (and it is small) allows to to work with a much simpler equation in the general gas law of PV = nRT. There are other assumptions, too. You can read more about it here.
http://www.chm.davidson.edu/vce/kineticmoleculartheory/basicconcepts.html