Thermodynamics: Spontaneity & Entropy
Chemical Kinetics, Equilibrium and Thermodynamics: - Kinetics: How _______ a _______ proceeds - Equilibrium: Amount of _______ present when equilibrium is reached - Thermodynamics: Why some changes happen _______ and others do not
Chemical Kinetics, Equilibrium and Thermodynamics: - Kinetics: How fast a reaction proceeds - Equilibrium: Amount of product present when equilibrium is reached - Thermodynamics: Why some changes happen spontaneously and others do not
Description of the Kinetics and Thermodynamics Aspects of a Process: - Spontaneous but slow process = _______ favorable but _______ unfavorable - Spontaneous and fast process = _______ and _______ favorable
Description of the Kinetics and Thermodynamics Aspects of a Process: - Spontaneous but slow process = Kinetically favorable but thermodynamically unfavorable - Spontaneous and fast process = Kinetically and thermodynamically favorable
Dispersal of Matter and Energy: - The entropy of a system increases with: a.) Increasing _______ _______ b.) Increasing freedom of _______ c.) Increasing _______
Dispersal of Matter and Energy: - The entropy of a system increases with: a.) Increasing molecular complexity b.) Increasing freedom of motion c.) Increasing temperature
Entropy Change and Phase Transitions: - The entropy of a substance increases (ΔS > 0) as it transforms from a: relatively ordered _______ --> less-ordered _______ --> still less-ordered _______
Entropy Change and Phase Transitions: - The entropy of a substance increases (ΔS > 0) as it transforms from a: relatively ordered solid --> less-ordered liquid --> still less-ordered gas
Entropy Change in the Surroundings: - The entropy change experienced by the surroundings of a chemical reaction depends on whether the reaction is: a.) _______ (heat flows into the surroundings) OR b.) _______ (heat flows from the surroundings into the system) ∆S_sur = -∆H_sys/T_Kelvin
Entropy Change in the Surroundings: - The entropy change experienced by the surroundings of a chemical reaction depends on whether the reaction is: a.) Exothermic (heat flows into the surroundings) OR b.) Endothermic (heat flows from the surroundings into the system) ∆S_sur = -∆H_sys/T_Kelvin
Entropy Change in the Surroundings: At constant T and P - An endothermic reaction (system) _______ the entropy of the surroundings because heat flows from the _______ into the _______ - An exothermic reaction (system) _______ the entropy of the surroundings because the heat generated by the reaction flows into the _______
Entropy Change in the Surroundings: At constant T and P - An endothermic reaction (system) decreases the entropy of the surroundings because heat flows from the surroundings into the system - An exothermic reaction (system) increases the entropy of the surroundings because the heat generated by the reaction flows into the surroundings
Entropy Changes and Temperature: - Raising the temperature of a substance results in: a.) More extensive _______ of the particles in solids b.) More rapid _______ of the particles in liquids and gasses - At higher temperatures, the distribution of the _______ _______ of the particles of a substance is _______ (more disperse) than at lower temperatures a.) Thus, the entropy of any substance _______ with increasing temperature
Entropy Changes and Temperature: - Raising the temperature of a substance results in: a.) More extensive vibration of the particles in solids b.) More rapid translations of the particles in liquids and gasses - At higher temperatures, the distribution of the kinetic energy of the particles of a substance is broader (more disperse) than at lower temperatures a.) Thus, the entropy of any substance increases with increasing temperature
Entropy and Molecular Complexity: - The greater the numbers of atoms (regardless of their masses) in a molecule: a.) The greater the ways in which the molecules can _______ b.) The greater the number of possible configurations of _______ and _______ of the atoms c.) Thus, the _______ the entropy of the system
Entropy and Molecular Complexity: - The greater the numbers of atoms (regardless of their masses) in a molecule: a.) The greater the ways in which the molecules can vibrate b.) The greater the number of possible configurations of locations and energies of the atoms c.) Thus, the greater the entropy of the system
Entropy and Second Law of Thermodynamics: - In any spontaneous process there is always an _______ in the entropy of the universe ΔSuniv = ΔSsys + ΔSsurr > 0 ΔSuniv = ΔSsys + ΔSsurr = ΔSsys + (qsurr / T) qsurr: heat exchange experienced by the _______ T: _______ temperature - This equation may be used to predict the _______ of a process. - Notice that to make this prediction it is necessary to determine both, the entropy change for the _______ and the entropy change for the _______
Entropy and Second Law of Thermodynamics: - In any spontaneous process there is always an increase in the entropy of the universe ΔSuniv = ΔSsys + ΔSsurr > 0 ΔSuniv = ΔSsys + ΔSsurr = ΔSsys + (qsurr / T) qsurr: heat exchange experienced by the surroundings T: Kelvin temperature - This equation may be used to predict the spontaneity of a process. - Notice that to make this prediction it is necessary to determine both, the entropy change for the system and the entropy change for the surroundings
Entropy and Second Law of Thermodynamics: If ΔSuniv > 0: - ΔSuniv _______ - Spontaneous process in the direction _______ If ΔSuniv < 0: - ΔSuniv _______ - Spontaneous process in the _______ direction If ΔSuniv = 0 - ΔSuniv remains the _______ - Equilibrium: _______ process
Entropy and Second Law of Thermodynamics: If ΔSuniv > 0: - ΔSuniv Increases - Spontaneous process in the direction written If ΔSuniv < 0: - ΔSuniv Decreases - Spontaneous process in the opposite direction If ΔSuniv = 0 - ΔSuniv remains the same - Equilibrium: reversible process
Entropy: - Shown as (____) - State function that measures the _______ of motion of particles in a system and the _______ of their _______ of motion
Entropy: - Shown as (S) - State function that measures the freedom of motion of particles in a system and the dispersal of their energy of motion
Non-spontaneous Processes: - Will not take place unless they are '_______' by the ongoing input of energy from an _______ source - A process that is spontaneous in one direction under a particular set of conditions, is _______ in the reverse direction.
Non-spontaneous Processes: - Will not take place unless they are 'driven' by the ongoing input of energy from an external source - A process that is spontaneous in one direction under a particular set of conditions, is nonspontaneous in the reverse direction.
Spontaneous Processes: - Occur without ongoing _______ _______ under certain conditions - They are _______ (unidirectional) - Can be very _______ or very _______ a.) The spontaneity of a process is NOT correlated to the _______ of the process
Spontaneous Processes: - Occur without ongoing external intervention under certain conditions - They are irreversible (unidirectional) - Can be very fast or very slow a.) The spontaneity of a process is NOT correlated to the speed of the process
Standard Molar Entropies: - At 25C, the standard molar entropy (S) of any substance is the energy dispersed into one _______ of that substance in its _______ state - Standard entropies are determined for one mole of substance at a pressure of 1 _______ and a temperature of ____ K. - S(elements) cannot = 0: All substances have _______ entropies at temperatures _______ absolute zero
Standard Molar Entropies: - At 25C, the standard molar entropy (S) of any substance is the energy dispersed into one mole of that substance in its standard state - Standard entropies are determined for one mole of substance at a pressure of 1 bar and a temperature of 298 K. - S(elements) cannot = 0: All substances have positive entropies at temperatures above absolute zero
Third Law of Thermodynamics: - The entropy of a pure _______ substance at absolute zero (0 K) is _______
Third Law of Thermodynamics: - The entropy of a pure crystalline substance at absolute zero (0 K) is zero
Ways to Predict if a Reaction is Spontaneous (favoring the products; K > 1): UNIVERSE = _______ + _______ - System = _______ Reaction - Surroundings = _______ _______
Ways to Predict if a Reaction is Spontaneous (favoring the products; K > 1): UNIVERSE = System + Surroundings - System = Chemical Reaction - Surroundings = Everything else