Raven Johnson Biology Chapter 8 Answers to Review Questions 1. The two states of energy are kinetic and potential. These two must occur together because every electron that is lost by one molecule must be gained by another. Oxygen is one of the most common electron acceptors in a redox reaction. The Second Law of Thermodynamics states that entropy increases, where entropy is energy so random and dissipated that it can't be used for work.
Heat is the energy of random molecular motion.
Entropy is a tendency toward disorder in the universe. Free energy is the energy present in the chemical bonds of a molecule, minus the energy lost to entropy. In exergonic reactions, products contain less energy or more disorder than the reactants, release energy, and proceed spontaneously. In endergonic reactions, products contain more free energy or more disorder than reactants and require an input of energy to proceed. Activation energy is the energy required to get spontaneous reactions going.