Thermodynamics and Energy Conversion Quiz

Thermodynamics and Energy Conversion

• Forms of energy include kinetic (object in motion) and potential (stored energy) such as heat, chemical, electrical, gravitational, optical, electrostatic, wind, and nuclear.
• Potential energy can be converted to kinetic energy, which is the form that does work.
• A thermodynamic system is a part of the universe under consideration, separated from the rest of the universe by a boundary, known as the surroundings.
• Thermodynamic potential is defined by parameters such as pressure, volume, temperature, enthalpy, and entropy.
• The first law of thermodynamics states that energy cannot be created or destroyed, only transformed from one form to another, and the total energy in the universe remains constant.
• Enthalpy is a property of a system reflecting its capacity to exchange heat with the surroundings, and its change can be measured.
• Heat always transfers from a hotter object to a cooler one, in exothermic and endothermic processes.
• The unit of energy, work, or heat is the joule, where 1 calorie equals 4.184 joules.
• Hess's Law states that the enthalpy change for a reaction carried out in a series of steps is equal to the sum of the enthalpy changes for the individual steps.
• The second law of thermodynamics states that the entropy of the universe increases, and highly ordered systems move towards more disorder.
• Entropy is a measure of the randomness of a system, related to the various modes of motion in molecules.
• Thermodynamic free energy is the maximum amount of chemical energy derived from a spontaneous reaction that can be utilized to do work, or the minimum amount of energy that must be supplied to make a non-spontaneous reaction occur.

Chemical Equilibrium and Reaction Rates

• At equilibrium, the rates of the forward and reverse reactions are equal, and the concentrations of the reactants and products are constant.
• The equilibrium constant (Keq) represents the unchanging concentrations of the reactants and products in a chemical reaction at equilibrium.
• The equilibrium constant can be calculated using the molar concentrations of all species in an equilibrium reaction.
• The ∆G at equilibrium is zero, indicating no net flow in either the forward or reverse direction and that neither process is favored.
• Le Châtelier’s Principle states that if an external stress is applied to a system at equilibrium, the system adjusts to partially offset the stress.
• Changes in concentration, pressure, volume, and temperature can shift the equilibrium position according to Le Châtelier’s Principle.
• For an endothermic reaction, an increase in temperature decreases the equilibrium constant, while for an exothermic reaction, it increases the equilibrium constant.
• Adding a catalyst does not change the equilibrium constant (K) or shift the position of an equilibrium system, but it speeds up the reaction.
• The rate of a chemical reaction depends on the concentration of reacting species, reaction temperature, presence of catalysts, and the nature of the reactants.
• Catalysis involves a material that promotes or increases the rate of a reaction without undergoing any permanent chemical change.
• Enzymes are biological catalysts that permit reactions to occur under conditions the body can tolerate and can process millions of molecules every second.
• Metabolism is the sum of all chemical reactions within a living organism and can be subdivided into two categories: catabolism and anabolism.