>>19868913>moleculesThey aren't indivisible, they are composed of atoms, which are in turn composed of subatomic particles such as protons and electrons, and further down - quarks.
All changes above the indivisible level, including chemical reactions, are caused by the movement of the indivisible particles in accordance to the laws of physics, such as gravitation and other dynamics. The movement of said particles can theoretically all be calculated, like that of a chain of dominoes.
It goes without saying that if you know the movement of each particle in time, you have predicted the future.