Final answer:
When a hand grenade explodes, chemical energy is converted to thermal, kinetic, and sound energy; heating the gases, propelling fragments, and creating a shock wave.
Step-by-step explanation:
When a hand grenade explodes, the stored chemical energy in the explosive is rapidly converted to thermal energy, kinetic energy, and sound energy. This transformation begins with the ignition of the grenade's fuse, which triggers the explosion of the explosive charge. The chemical energy contained in the explosive is then converted to thermal energy, creating intense heat and causing a rapid expansion of gases. This expansion results in a high-pressure shock wave that propagates through the surrounding air (sound energy), as well as providing the force to accelerate the grenade's casing fragments to high velocity (kinetic energy). Thus, the primary exchanges of energy are from chemical to thermal, and from thermal to kinetic and sound energy.