Chapter 20 Flashcards
ATP
a high-energy molecule that serves most commonly as a store and source of energy in organisms
coupling of reactions
the pairing of reactions of which one releases enough free energy for the other to occur
entropy (S)
a thermodynamic quantity related to the number of ways the energy of a system can be dispersed through the motions of its particles
free energy (G)
a thermodynamic quantity that is the difference between the system’s enthalpy and the product of the absolute temperature and the system’s entropy: G = H − TS
microstate
an instantaneous, quantized state of a system of particles throughout which the total energy of the system is dispersed
second law of thermodynamics
a law stating that a process occurs spontaneously in the direction that increases the entropy of the universe
spontaneous change
a change that occurs under specified conditions without an ongoing input of external energy
standard entropy of reaction
the entropy change that occurs when all components are in their standard states
standard free energy change
the free energy change that occurs when all components of a system are in their standard states
standard free energy of formation
the standard free energy change that occurs when 1 mol of a compound is made from its elements with all components in their standard states
standard molar entropy
the entropy of 1 mol of a substance in its standard state
third law of thermodynamics
a law stating that the entropy of a perfect crystal is zero at 0 K
