Variation of Heat Capacity with Temperature

This text discusses the variation of heat capacity with temperature and how it can be used to calculate the enthalpy change for a reaction.

The first three terms of a power series are used to represent the variation of heat capacity with temperature, and the enthalpy change is calculated by integrating the heat capacity over the temperature range.

Questions

1. What is the difference between heat capacity and enthalpy?
2. How does heat capacity vary with temperature?
3. How can the enthalpy change for a reaction be calculated using heat capacity data?

Answers

1. Heat capacity is the amount of heat required to raise the temperature of a substance by 1 degree Celsius. Enthalpy is the total heat content of a substance.
2. Heat capacity can vary with temperature because the energy required to break and form bonds in a substance can change with temperature.
3. The enthalpy change for a reaction can be calculated using heat capacity data by integrating the heat capacity over the temperature range of the reaction.