An endothermic reaction is the opposite. This is when a reaction starts colder and ends up hotter, taking in energy from start to finish. In an endothermic reaction, the system gains heat as the surroundings cool down. In an exothermic reaction, the system loses heat as the surroundings heat up.
I think it's coal as you use it for bbqs and train drivers use coal too. I'm pretty sure it's coal, but I'm not 100% sure. Hoped this helps.
Answer:
all bulbs will light up once the switch is closed
Answer: Density is a measure of mass per volume. The average density of an object equals its total mass divided by its total volume.
Explanation:
pretty self explanitory. (jk i googled it)