In: Chemistry
State the condition(s) under which the following equations can be applied: (a) ?S = ?H / T , (b) S(T = 0) = 0 , (c) dS = CpdT / T , (d) dS = dq / T
a)
This is applicable for the phase transition. The reversible phase transition occurs at constant temperature and pressure. The reversible heat is the enthalpy change for the transition while entropy change is the change in enthalpy divided by temperature. And it's different for entropy of fusion that is melting and entropy of vaporatisation that is boiling temperature.
b). S(T=0)= 0
This condition is applicable to the third law of thermodynamics, where a temperature is absolutely zero.
c).
This is applicable for heating or cooling of a system. at constant pressure from initial temperature to the final temperature. where molar heat capacity is constant and no phase transition occur.
d).
In a thermodynamic process, temperature of the object changes when heat is applied on the object. Therefore as heat energy increases the temperature of the object increases and vise verse.