Question

The mathematical equation of enthalpy (H) is:

• A. \( H = U + pV \)
• B. \( H = U - pV \)
• C. \( H = \frac{U}{pV} \)
• D. \( H = pV \)

Hint:

Remember that enthalpy (\( H \)) is the sum of internal energy (\( U \)) and the energy associated with pressure and volume (\( pV \)) in thermodynamic systems.

Answer 1

The Correct Option is A

The mathematical equation for enthalpy (\( H \)) is given by: \[ H = U + pV \] where:
- \( H \) is the enthalpy,
- \( U \) is the internal energy of the system,
- \( p \) is the pressure,
- \( V \) is the volume.
This equation is derived from the first law of thermodynamics and represents the total energy of a system, including both the internal energy and the energy required to "push" against the system's surroundings due to pressure and volume.
- Option (2) \( H = U - pV \) is incorrect because it doesn't represent the correct relation between enthalpy, internal energy, pressure, and volume.
- Option (3) \( H = \frac{U}{pV} \) is also incorrect as it introduces an unnecessary division of \( U \) by \( pV \), which doesn't match the definition of enthalpy.
- Option (4) \( H = pV \) is incorrect because it doesn't account for the internal energy \( U \), which is an essential part of the enthalpy calculation.
Thus, the correct answer is option (1): \( H = U + pV \).