I had an examon this on Friday, I'm pretty positive theanswer is C. The reason is when there is combusion, there is an exothermic change, or energy is being released
Answer:
The use of metal salts. some of the compound produce intense colors when they are burned
C. Their components can be separated by physical processes.
Well physical would be if you have Clay and you molded into a new shape or if you put butter on your toes and it melts or water evaporating from the surface of the ocean chemical changes would be milk going sour jewellery tarnishing which means turning into a different color or rust bread putting it in the oven and turning it into toes or rust forming on the nail that is left outside