Light is just a form of energy. There are photochemical reactions that only take place in the presence of light, but in general it's not possible to answer the question unless you get more specific about precisely which chemicals and how much light of what frequency you're talking about.
Hydrogen peroxide and a phenyl oxalate ester are combined inside a glow stick. When these two chemicals mix, they undergo a chemical reaction that produces light.
Animals such as fireflies contain two chemicals, luciferin and luficerase. When combined with oxygen, they give off light.
These chemicals are called reactants.
Depends on the chemicals, you get a different reaction from different ones.
A combination of chemicals is known as a reaction. When two chemicals, which are referred to as reactants, are combined, they for a chemical compound.
The mass of the two chemicals are just combined, and are never changed. They may change forms, like from a solid to a gas, but the mass is always the same.
Yes
Chemicals yes, elements however, no. Elements are themselves chemicals, Burn hydrogen in oxygen and you'll end up with water, another chemical.
When a red light and a green light are combined, the color produced is yellow.
A mixture contains 2 or more chemicals that are not chemically combined, meaning they can be physically separated. Examples include saltwater and air.
water, hydrogen peroxide
A mixture.