CBSE Class 11-science Chemistry Thermodynamics
Introduction to ThermodynamicsThe universe can be divided into a system and its surroundings. System can be open, closed and isolated.
State function depends on the state of the system and not on the path. The first law of thermodynamics states that the energy of the universe is constant.
Measurement of dU and dHHeat capacity is the quantity of heat energy required to raise the temperature of body by 1 degree C.
Heat change associated with chemical reactions can be measured using a calorimeter.
Hess's LawEnthalpy is a measurement of the heat content of a reactant or product.
In Exothermic reactions energy is released and in endothermic reactions energy is absorbed.
By Hess's law heat evolved or absorbed in a chemical reaction is same whether the reaction takes place in a single step or follows a series of steps.
Enthalpy ChangeEnthalpy of phase change is the enthalpy when one mole of pure substance changes phase.
Ionisation enthalpy is the enthalpy change when one mole of electrons is removed from one mole of gaseous atoms under standard conditions.
Born Haber helps calculating lattice enthalpy.
Entropy and Gibbs EnergyEntropy is the measure of randomness or disorder of the system.
Gibbs energy function gives amount of useful work done.
The sign and magnitude of the free energy change of a chemical reaction predicts the spontaneity of a chemical reaction.