Question

If the enthalpy change for a process at constant pressure is negative, what type of process is it likely to be?

• A. Endothermic
• B. Exothermic
• C. Isothermal
• D. Adiabatic

Hint:

Enthalpy Change Sign Convention. \(\Delta H>0\): Endothermic (Heat absorbed). \(\Delta H<0\): Exothermic (Heat released). (At constant pressure, \( \Delta H = Q_p \)).

Answer 1

The Correct Option is B

Enthalpy change (\(\Delta H\)) at constant pressure represents the heat absorbed or released by the system during a process.
- If \(\Delta H\) is positive (\(\Delta H>0\)), the process absorbs heat from the surroundings; it is endothermic.
- If \(\Delta H\) is negative (\(\Delta H<0\)), the process releases heat to the surroundings; it is exothermic.
- Isothermal means constant temperature (\(\Delta T = 0\)).
- Adiabatic means no heat exchange with the surroundings (\(Q = 0\)).
Since the enthalpy change is given as negative, the process releases heat and is therefore exothermic.