1What is the significance of differences in affinities of the sample component component to that of the solvent and the stationary phase?2.why is it important to cover the developing chamber (the beaker) tightly with aluminum foil while the chromatogram is developing?
1If the molecules have a greater affinity form the solvent then they will move with the solvent and go higher up the parerIf the molecules have a greater affinity for the parer then they will grab on to the paper and not be pulled as far by the solventThese compounds will not move very far up the paper2To prevent your solvent from evaporating off the paper while you are trying to do a chromatographAs you know, most liquids are volatile to some degreeIn any liquid there are always some molecules going from liquid to gas and some molecules going from gas to liquidIn an open system, once they have chaged phase to gas they will wizz off into the atmosphere and not come back, so you see evaporation, and you lose solventIn a closed system a dynamic equlibrium will form, where a certain amount of molecules are gas and a certain amount liquidThe molecules will shift back and forth, but the overall concentration of solvent vapour in the chamber will remain constantSo, since the vapour pressure of your solvent in a sealed tank is constant and at equlibrium your solvent on the paper will not evaporate.
It is more likely to give up as it has less charge
