Not AFAIK. A simple capacitor is two metal plates separated by an insulator, allowing an electrical charge to accumulate. Discharge would only be limited by the current-carrying capacity of the wiring.

Limited by material. They store electric charge by using thin layers of insulating material and pooling negative charge on one side and positive on the other. You can puncture the material and release energy as a typical conductor, it's not stored chemically.

Not generally, no. Capacitors usually store electrons in a conductor so they are free to move instantly. Movement of free electrons within a conductor is not considered a chemical reaction.