Chapter 15 of Chemical Thermodynamics Review Questions with complete Solutions Rated 100%

Chapter 15 of Chemical Thermodynamics Review Questions with complete Solutions Rated 100% Absolute Entropy (of a substance) - Answers The entropy of a substance relative to its entropy in a perfectly ordered crystalline form at 0 K (where its entropy is zero) Bomb Calorimeter - Answers A device used to measure the heat transfer between system and surroundings at constant volume Bond Energy - Answers The amount of energy necessary to break one mole of bonds in a gaseous substance to form gaseous products at the same temperature and pressure Calorimeter - Answers A device used to measure the heat transfer that accompanies a physical or chemical change Dispersal of Energy - Answers The degree to which the total energy of a system can be distributed among its particles Dispersal of Matter - Answers The degree to which the particles of a sample can be distributed in space; aka disorder Endothermic Process - Answers A process that absorbs heat Enthalpy Change (Delta H) - Answers The quantity of heat transferred into or out of a system as it undergoes a chemical or physical change at constant temperature and pressure Entropy (S) - Answers A thermodynamic state function that measures the dispersal of energy and the dispersal of matter (disorder) of a system Equilibrium - Answers A state of dynamic balance in which the rates of forward and reverse processes (reactions) are equal; the state of a system when neither the forward nor the reverse process is thermodynamically favored Exothermic Process - Answers A process that gives off (releases) heat First Law of Thermodynamics - Answers The total amount of energy in the universe is constant (aka the Law of Conservation of Energy); energy is neither created nor destroyed in ordinary chemical reactions and physical changes Gibbs Free Energy (G) - Answers The thermodynamic state function of a system that indicates the amount of energy available for the system to do useful work at constant T and P. It is defined as G = H - TS; aka free energy Heat of Formation - Answers See standard molar enthalpy of formation Hess's Law of Heat Summation - Answers The enthalpy change for a reaction is the same whether it occurs in one step or a series of steps Internal Energy (E) - Answers All forms of energy associated with a specific amount of a substance Kinetic Energy - Answers The energy of motion. The kinetic energy of an object is equal to one half its mass times the square of the velocity Law of Conservation of Energy - Answers Energy cannot be created or destroyed in a chemical reaction or physical change; it may be changed from one form to another; see First Law of Thermodynamics Mole of Reaction (mol rxn) - Answers The amount of reaction that corresponds to the number of moles of each substance shown in the balanced equation Nonspontaneous Change - Answers A change for which the collection of reactants is more stable than the collection of products under the given conditions; aka reactant-favored change Potential Energy - Answers The energy that the system possesses due to the virtue of its position or composition Pressure-Volume Work - Answers Work done by a gas when it expands against an external pressure, or work done on a system as gases are compressed or consumed in the presence of an external pressure Product-Favored Change - Answers See Spontaneous Change Reactant-Favored Change - Answers See Nonspontaneous Change Second Law of Thermodynamics - Answers The universe tends toward a state of greater disorder in spontaneous processes Spontaneous Change - Answers A change for which the collection of products is more stable than the collection of reactants under the given conditions; aka product-favored change Standard Enthalpy Change (Delta H^0) - Answers The enthalpy change in which the number of moles of the reactants specified in the balanced chemical equation, all at standard states, is converted completely to the specified number of moles of products, all at standard states Standard Entropy Change (Delta S^0) - Answers The entropy change in which the number of moles of the reactants specified in the balanced chemical equation, all at standard states, is converted completely to the specified number of moles of products, all at standard states Standard Gibbs Free Energy Change (Delta G^0) - Answers The indicator of spontaneity of a process at constant T and P. If it is negative, the process is product-favored (spontaneous); if it is positive, the process is reactant-favored (nonspontaneous)