Question

Select the wrong option regarding enthalpy

• A. Enthalpy is the measure of total heat in a thermodynamic system where pressure is constant
• B. It is represented as \(\Delta H = \Delta E + P \Delta V\)
• C. It is a measure of disorder in a thermodynamic system
• D. It represents the heat constant of a system

Hint:

• Enthalpy \(H = E + PV\) (or \(U+PV\)).
• Change in enthalpy \(\Delta H = q_p\) (heat exchanged at constant pressure).
• For processes at constant pressure, \(\Delta H = \Delta E + P\Delta V\).
• Entropy (S) is the measure of disorder or randomness in a system.

Answer 1

The Correct Option is C

Enthalpy, denoted by \(H\), is a fundamental concept in thermodynamics, especially when dealing with chemical reactions and processes at constant pressure. Let's explore this concept and identify the incorrect statement regarding enthalpy.

• Option 1: Enthalpy is the measure of total heat in a thermodynamic system where pressure is constant.
  This statement is accurate. Enthalpy accounts for the heat content of a system under constant pressure conditions.
• Option 2: It is represented as \(\Delta H = \Delta E + P \Delta V\).
  Correct. This is the mathematical definition of the change in enthalpy (\(\Delta H\)), where \(\Delta E\) is the change in internal energy, \(P\) is pressure, and \(\Delta V\) is the change in volume.
• Option 3: It is a measure of disorder in a thermodynamic system.
  This is incorrect. The measure of disorder in a system is described by entropy, not enthalpy.
• Option 4: It represents the heat constant of a system.
  Correct in the context of constant pressure processes; enthalpy changes reflect the heat absorbed or released.

The wrong option regarding enthalpy is thus Option 3, as it confuses enthalpy with entropy.