Resumen de A Visual Aid in Enthalpy Calculations
This article discusses the use of enthalpy-temperature diagrams for reactants and products as a visual aid in the teaching of reaction-enthalpy calculations. By the use of such diagrams the division of the process into a part involving a chemical reaction without a temperature change and a part involving only a temperature change is made visually concrete. The diagrams afford a ready explanation of why enthalpies of reactions can change in sign and magnitude as the temperature changes. This change is easily seen to be related to the differences in molar heat capacities of reactants and products. The connection between the sign of the enthalpy of reaction and the sign of ΔT is also very readily apparent from the diagrams. The approach outlined here should prove especially useful for students whose primary learning style is visual.
