define kinetic energy and thermal energy. describe what happens to each as the temperature of a substances…
define kinetic energy and thermal energy. describe what happens to each as the temperature of a substances increases.
Answer
Brief Explanations:
- Kinetic Energy (of particles in a substance): Energy of motion. For a particle, $KE = \frac{1}{2}mv^2$ (where $m$ is mass, $v$ is velocity). In a substance, it’s the energy of its atoms/molecules moving (vibrating, translating, rotating).
- Thermal Energy: Total kinetic energy of all particles in a substance, plus potential energy from particle interactions (related to temperature, mass, and phase).
- Effect of Temperature Increase:
- Kinetic Energy: As temperature rises, particles move faster (higher average $v$), so the average kinetic energy of particles increases (temperature is proportional to average kinetic energy of particles in a substance, for ideal gases $KE_{avg} \propto T$).
- Thermal Energy: Since thermal energy depends on the total kinetic energy of all particles (and potential energy, but for temperature increase without phase change, kinetic energy dominates), as temperature (and average particle KE) increases, and if mass is constant, thermal energy increases (more total energy from faster-moving particles).
Answer:
- Kinetic Energy: Energy of motion (e.g., of a substance’s atoms/molecules).
- Thermal Energy: Total energy (kinetic + potential from interactions) of all particles in a substance.
- As Temperature Increases:
- Kinetic Energy: Average kinetic energy of particles increases (particles move faster).
- Thermal Energy: Thermal energy increases (due to more total kinetic energy of particles, and/or potential energy changes if phase changes, but generally increases with temperature for a substance).