How is chemical energy converted into light energy?

Answer 1

As a chemist I can tell you that you have witnessed chemical energy being converted to light energy everytime you see a light bulb powered by a battery. The energy in the battery is stored as chemical energy, which is released by electrons leaving chemicals and flowing through the filament in the light bulb. As the electrons flow through the filament, they release some of their energy in the form of light.

That is a rather simplified explanation, but if you want more detail, you better learn some indepth chemistry and physics first.