How do you derive kirchhoff's equation thermodynamics?

Answer 1

for the rxn

A ---> B, where A is at temp T1 and B at temp T2

1) At constant pressure H1= HB - HA

A first converts to B at temp T1 and reh temp rises to T2, thus the heat supplied for this change is Cp(T2-T1), Cp is the heat capacity of products.

Hence the heat change will be given by H(path1)= Cp(T2-T1)+H1

2) first the temp of A is raised to T2. the heat supplied for this change is Cp'(T2-T1) , Cp' is the heat capacity of reactants. now A is changed to B with an enthalapy change of H2. H(path2)= Cp'(T2-T1)+H2.

H(path1)=H(path2)

H2-H1/T2-T1=Cp-Cp'

Answer 2

Kirchhoff's equation in thermodynamics is derived by considering the change in enthalpy of a system at constant pressure and temperature. It relates the temperature dependence of enthalpy to the heat capacity at constant pressure. By applying the first law of thermodynamics and the definition of heat capacity at constant pressure, Kirchhoff's equation can be derived.

Answer 3

Well, hello there, friend! Deriving Kirchhoff's equation in thermodynamics is like painting a happy little tree. You start by considering the change in enthalpy with respect to temperature at constant pressure. By using the definition of heat capacity at constant pressure, you can then derive Kirchhoff's equation, which relates the change in enthalpy to the heat capacity at constant pressure and the temperature change. Just remember to approach it with a calm mind and gentle brushstrokes, and you'll see the beauty of thermodynamics unfold before your eyes.