I think you should be more specific as the stability of a chemical formulation is dependent on many factors. Are you referring to developers or other chemistry? Liquids or powders?
Many manufacturers have this information on their spec. sheets. Go to their web sites and take a look. Freestyle also has links to spec. sheets on many photo chemicals.
It also depends on if the container is full or partially full, as more air means more oxidation. I use marbles to eliminate the air in my one-shot Ilfosol 3 developer.
Finally, as richard ide says - depends on what chemicals and conditions you are talking about.