Chemistry Thermochemistry BUMHS 2024
PMDC Verified Question 20 of 81
Units of change in enthalpy of a system are:
A
\( ^\circ \text{C} \)
B
cc
C
J
D
Pa
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: J
Concept:

Enthalpy (\( H \)) is a measure of total thermodynamic energy. Therefore, the change in enthalpy (\( \Delta H \)) must be reported in fundamental energy units.

Solution:

  • The SI unit for all forms of energy (including work, heat, internal energy, and enthalpy) is the Joule (J).


  • In chemistry, this is often scaled to kilojoules (kJ) or kilojoules per mole (\( \text{kJ/mol} \)), but the base unit remains the Joule.


Why other options are incorrect:

Pa (Pascals) measures pressure. cc (Cubic centimeters) measures volume. \( ^\circ \text{C} \) measures temperature. None of these measure energy.

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