If friction is caused by the reaction of molecules between the two surfaces, why doesn't a force act when you lift the object? You have to break the bonds either way, be it lifting the object or moving it. Why is it that we don’t have to overcome the force required to break the cluster of molecules?
Thank you
 A: It does!
In most cases the force is too small to be noticable however it is there. I spent a happy few months measuring the friction between carbon whiskers, and the adhesion force between the whiskers was large enough to cause a noticable deformation of the whiskers when I separated them. In fact you had to add the adhesion force to the applied load to get a correct value for the friction coefficient.
For large objects the force is usually small compared to the weight of the object however in special cases, e.g. very clean surfaces, it is large enough to cause cold welding.
A: If you have an object sitting on a table, what's actually happening on the atomic scale is the electrons of the atoms on the table are repelling the electrons on the surface of the object.  The object is basically hovering over the table (but only be a very tiny amount).  Therefore, when you lift an object off a table, you don't normally have to overcome any kind of intermolecular force, except if the surfaces are attracted by some forces (which could for e.g. be magnetic, electrostatic, an air layer as in suction cups)
