A problem in chemical thermodynamics
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There is a question on chemical engineering thermodynamics: At temperature T, what is the pressure P of a superheated steam? Options: A. It equals the saturated vapor pressure at temperature T. B is determined based on the specific substance: C is less than the saturated vapor pressure at temperature T, while D is greater than or equal to the saturated vapor pressure at temperature T. Not sure which one to choose? If you know, please tell me the reason
According to thermodynamic principles, the pressure of superheated steam should be greater than or equal to the saturated steam pressure at the corresponding temperature. Therefore, option D, which is greater than or equal to the saturated vapor pressure at temperature T, should be the correct choice. .
It’s obvious; for example, for a temperature t, there is a corresponding saturated vapor pressure P. Superheating indicates that the saturation temperature is lower than t, and conversely, the pressure of superheated steam is lower than that of saturated steam
Two different answers came up. Does the original poster know which one is the correct answer?
According to the principles of thermodynamics, when a liquid and its vapor are in equilibrium, the saturated vapor pressure at the liquid surface is equal to the vapor pressure at that temperature. Therefore, option A is the correct choice. According to this theory, when the pressure of a superheated steam at temperature T is equal to the saturated vapor pressure at that same temperature, this superheated steam begins to evaporate partially into saturated vapor. Therefore, it is correct to choose A as the saturated vapor pressure at temperature T. Choosing B and D is incorrect, as they do not take into account the relationship between surface saturated vapor pressure and temperature in thermodynamic principles.
You can point out the reasons you give; if your parents didn’t teach you how to be a well-mannered person, then it’s like a grandson scolding his grandfather
I just said something that any normal person would think, so please stop speaking recklessly