The change in enthalpy at constant pressure, △H is equal to:
Correct answer: A. △H = q + P△V
- A. △H = q + P△V
- B. △H = △E- P△V
- C. △H = △E + P△V
- D. △H = q - P△V
Explanation
The change in enthalpy, ∆H, at constant pressure is equal to the sum of the heat absorbed or released, q, and the pressure-volume work, P∆V, done on or by the system during the process. This is because enthapy, H, is defined as the sum of internal energy, U, and the product of pressure and volume, PV, and at constant pressure, the change in enthalpy is equal to the heat transferred plus the Workdone.∆H = q + P∆V
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About Enthalpy
Enthalpy is the heat content of a system measured at constant pressure, and its change indicates whether a reaction or physical process is endothermic or exothermic. The topic covers state functions, enthalpy diagrams, standard enthalpy of formation, combustion and neutralisation, and the relationship between ΔH and internal energy change.
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