Question

Explain me about thermodynamic principle of chapter metallurgy plz its urgent

Answer 1

Thermodynamics

There is an overlap between the study of physics and chemistry, known as Physical Chemistry. And here is where the concept of thermodynamics exits. Thermodynamics is the branch of science that deals with a relationship between thermal energy i.e. heat and other forms of energy.

Thermodynamics is the study of the energy transfer that occurs during chemical as well as physical changes. It also allows us to predict and measure these changes.


Thermodynamics in Metallurgy

The main thermodynamic concept we must concern ourselves with when it comes to metallurgy is Gibbs Free Energy. In thermodynamics, whether a process will happen spontaneously or not will be determined by Gibbs Free Energy. The symbol ΔG. If this value of ΔG is negative then the reaction will occur spontaneously. We will now look at two equations to arrive at ΔG

ΔG = ΔH – TΔS

ΔH is the change in enthalpy. Here a positive value will depict an endothermic reaction, while a negative value will be an exothermic reaction. So when the reaction is exothermic, it makes ΔG negative. ΔS is the Entropy or the randomness of molecules. This changes very sharply when the state of the matter changes. Another equation which relates the Gibbs Free Energy to the equilibrium constant is

ΔG° = RTlnKeq

Keq is the equilibrium constant. It is calculated by dividing the active mass of products by the active mass of reactants. R is the universal gas component. Now to attain a negative value of ΔG (which is desirable) the value of the equilibrium must be kept positive.