★Specialized Examination for Chemical Engineering ★ — One question per day (2015-12-23) — Points are awarded for participation
Thread Content
Points system for the daily question: Participation – 1~3 points; Correct answer – 5 points; In-depth analysis – 5~10 points. The answer is provided the day after. Due to limited capabilities, I am unable to provide more in-depth explanations for each question; therefore, on the second day, in addition to offering reference options, I will also remove the restriction on reading replies. I hope that all candidates can learn from one another and improve together! Daily Question (2015-12-23): 1. If Q and W represent the heat added to the system and the work done on the system by the surroundings, respectively, and △U, g△Z, and △u²/2 represent the changes in internal energy, potential energy, and kinetic energy per unit mass of fluid, then which of the following options represents the energy balance equation for an open system undergoing a steady-state process? A. △U + g△Z + △u²/2 = Q – W B. △U + g△Z + △u²/2 = W – Q C. △U + g△Z + △u²/2 + Q + W = 0 D. △U + g△Z + △u²/2 = Q + W Answer: D Actual exam question from the morning session in 2011
Choose D; the work done on the system is positive, while in the textbook the work done by the external environment on the system is negative
. If Q and W represent the heat added to the system and the work done on the system by the surroundings, respectively, and ΔU, gΔZ, and Δu²/2 represent the changes in the internal energy, potential energy, and kinetic energy per unit mass of fluid, then which of the following options represents the energy balance equation for an open system undergoing a steady process? C A、△U+g△Z+△u2/2=Q-W B、△U+g△Z+△u2/2=W-Q C、△U+g△Z+△u2/2+Q+W=0 D、△U+g△Z+△u2/2=Q+W
. If Q and W represent the heat added to the system and the work done on the system by the surroundings, respectively, and ΔU, gΔZ, and Δu²/2 represent the changes in the internal energy, potential energy, and kinetic energy per unit mass of fluid, then which of the following options represents the energy balance equation for an open system undergoing a steady process? A、△U+g△Z+△u²/2=Q-W B、△U+g△Z+△u²/2=W-Q C、△U+g△Z+△u²/2+Q+W=0 D、△U+g△Z+△u²/2=Q+W
I’m hesitating between C and D; thinking back to the principles of chemical engineering, it seems like D would be more appropriate, but I’m not sure!
D. △U + g△Z + △u²/2 = Q + W
1. If Q and W represent the heat added to the system and the work done on the system by the surroundings, respectively, and △U, g△Z, and △u²/2 represent the changes in the internal energy, potential energy, and kinetic energy per unit mass of fluid, then which of the following is the energy balance equation for an open system undergoing a steady process? A. DA, △U+g△Z+△u²/2=Q-W B. △U+g△Z+△u²/2=W-Q C. △U+g△Z+△u²/2+Q+W=0 D. △U+g△Z+△u²/2=Q+W