【Daily Question】Theoretical Foundation 2019.6.4
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Multiple-choice question: Which of the following statements regarding enthalpy is correct? ( ) (A) The enthalpy value of elements is always zero. (B) The change in enthalpy is zero during an isothermal process. (C) The change in enthalpy is zero during an adiabatic reversible process. (D) In a chemical reaction, the change in enthalpy of the system is not necessarily greater than the change in internal energy. Answer: D. Since the enthalpy change ΔH = ΔU + Δ(pV), it can be seen that if Δ(pV) < 0, then ΔH < ΔU. Hint: The answer can be found in the response
(D) The enthalpy change of a system in a chemical reaction is not necessarily greater than the change in internal energy
(D) The enthalpy change of a system in a chemical reaction is not necessarily greater than the change in internal energy
D. In chemical reactions, the enthalpy change of a system is not necessarily greater than the change in internal energy