Question

What is the difference between entropy, enthalpy, and heat transfer?

Answer 1

What is the difference between entropy, enthalpy, and heat transfer?

Entropy : It measures the amount of heat dispersed or transferred during a chemical process. It is expressed by a symbol (S). It measured in J/K. It has no requirements or limits and its change is measured by the division between heat change of the chemical process and the temperature.

We know that, an entropy increases. The value of entropy is positive and negative as well depending on the case.

Enthalpy : It is the amount of heat energy transferred in a chemical process under constant pressure. It is expressed by a symbol (H). It measured in J/mol. It can only be related to the heat change of the reaction under standard conditions.

In enthalpy, total energy of products greater than total energy of reactants. The value of enthalpy is positive for endothermic reactions and the value of enthalpy is negative for exothermic reactions.

Heat Transfer : It is the process of transfer of heat from high temperature reservoir to low temperature reservoir. The heat transfer can also take place within the system due to temperature difference at various points inside the system.

Three types of heat transfer are given below as -

(a) Conduction = The transfer of heat between two solid bodies is called as conduction. It depends on the difference in temperature of the hot and cold body.

Mathematically, we have

Q / t = A (T_hot - T_cold) / d

(b) Convection = The transfer of heat between solid surface and liquid is called as convection.

Mathematically, we have

q = h A (T_S - T)

(c) Radiation = When two bodies are at different temperature and separated by a distance, then the heat transfer between them is called as radiation.

Mathematically, we have

P = A (T⁴ - T_C⁴)