Chemistry Chapter 7 | 1st Year

Chapter 7 Notes | Chemistry 1st Year

 “Thermochemistry”

Index:

1. Introduction
2. Spontaneous And Non-Spontaneous Reactions
3. System, Surrounding And State Function
4. Internal Energy And First Law of Thermodynamics
5. Enthalpy
6. Hess’s Law of Constant Heat Summation

Key Points:

1. Substances exit because they possess energy. Energy can be transformed in form of heat and the study of heat changes accompanying a chemical reaction is called thermochemistry.
2. Whenever, a reaction happens, then the driving force is the enthalpy change, along with the entropy change. Both these parameters decide upon spontaneity of reaction.
3. Most of the thermodynamic parameters are state functions.
4. First law of thermodynamics is the law of conversation of energy and help us to understand the equivalence of heat and work.
5. When heat is supplied to the system at constant pressure, then it is the enthalpy change of the system. Anyhow, at constant volume, the heat supplied is just equal to internal energy change.
6. There is difference b/w heat and temperature. The amount of heat evolved or absorbed can be measured in laboratory by using glass calorimeter or bomb calorimeter.
7. According to Born-Haber cycle, another form of Hess’s law, the energy change in a cyclic process is always equal to zero. With the help of this cycle, we can calculate lattic energy of ionic crystals.