Is this statement correct, explain your reasoning: the amount of chemical energy in a flashlight's battery is equal to the light energy it emits to the environment.

YES

The amount of energy when it is transformed from one form to another is still the same or equal. 

The law of conservation of energy states energy cannot be destroyed nor created. Instead, it just transform from one form to another. 

There are different types of energy. They are:
1) Chemical Energy
2) Mechanical Energy 
   a) Kinetic energy
   b) Potential energy
         i. gravitational potential energy
         ii. elastic potential energy
3) Electrical Energy
4) Nuclear Energy

Chemical Energy can transform to thermal energy or electrical energy.
Mechanical Energy can transform to electrical energy