Final answer:
Energy is the capacity to do work and exists in forms like kinetic and potential energy. Particles with more kinetic energy have more freedom of movement. Free energy is the energy available for work in a system, and activation energy is the minimum energy required for a reaction.
Step-by-step explanation:
Energy is a fundamental concept in physics that describes the capacity to do work or cause change; it exists in various forms such as kinetic energy, which is the energy of motion, and potential energy, which is the energy stored in an object due to its position or arrangement. When particles move with more freedom, they generally have more kinetic energy; as temperature increases, the kinetic energy of particles also increases, leading to more freedom of movement. Conversely, if there is a decrease in temperature, the kinetic energy of particles will decrease, resulting in less freedom of movement. Free energy, specifically Gibbs free energy, is the energy available to do work in a system, and is a key concept when discussing chemical reactions. Activation energy is the minimum energy that reacting species must have in order to undergo a specified reaction.