Select the correct answer. Which statement is true of a chemical change? A. It involves changes in the molecular structure. B. It involves changes in phase but not changes in the molecular structure. C. It involves dissolving one substance into another. D. It involves a change in the state, or phase, of a substance. E. It involves the process of separating two or more dissolved substances.

Refrigerant-134a flows through a carnot heat pump cycle at 0.5 kg/s. it is known that the maximum absolute temperature in the cycle is 1.1 times the minimum absolute temperature, and the net power input to the cycle is 2.5 kw. if the refrigerant changes from a saturated vapor to a saturated liquid during the heat rejection process, determine the maximum magnitude of the enthalpy of vaporization for this process in kj/kg (with 3 significant figures).