★Specialized Examination for Chemical Engineering ★ — One question per day (2015-12-8) — Points are awarded for participation
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This post was last edited by zshiwei2008 on 2015-12-9 at 10:04. 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 next day. 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 (2015-12-8): 1. The overall conversion rate of the reaction system is higher than the one-pass conversion rate. The judgment for this sentence is ( ). A. Correct B. Incorrect C. Uncertain 2. A mixture of A and B is separated by distillation to yield pure A and B; the boiling points of A and B at the operating pressure are 319.41 K and 349.9 K respectively. The tower top condenser should preferably use ( ) as a coolant. A. Hot water B. Deep well water C. Air D. Frozen saline Solution. Answer: 1 C. C is the correct answer, as it is not specified in the text whether the process is a cyclic one or not. During the cycling process, this statement is correct. Answers A and B are incorrect. 2 B B. The answer is correct. The boiling point of the mixture given in this question ranges from 40 °C to 80 °C; therefore, deep well water can be used once to condense the vapor during condensation at the top of the tower. Options A, C, and D are incorrect.
C and B because it is not specified before this passage whether the process is a cyclic one. The boiling point of the mixture ranges from 40°C to 80°C, so a single supply of deep well water is sufficient for condensing the vapor during condensation at the top of the tower.
1 A. Correct 2 B. Deep well water
1. The overall conversion rate of the reaction system is higher than the one-pass conversion rate. The judgment for this sentence is (c). A. Correct B. Incorrect C. Uncertain 2. A mixture of A and B is separated by distillation to yield pure A and B; the boiling points of A and B at the operating pressure are 319.41 K and 349.9 K respectively. The tower top condenser should preferably use ( ) as a coolant. A. Hot water B. Deep well water C. Air D. Frozen brine 【Answer】B 【Explanation】The boiling point of the mixture in question is between 40°C and 80°C; therefore, deep well water can be used once for condensing the vapor during condensation at the top of the tower.
1.b The one-way conversion rate is definitely greater than or equal to the total conversion rate. 2.b The top condensation temperature should be maintained between 46.41° and 76.9°; well water can be used – frozen brine is not cost-effective
1. The overall conversion rate of the reaction system is higher than the one-pass conversion rate. The judgment for this sentence is (C. Indeterminable). 2. The mixture of A and B is separated by distillation into high-purity A and B, whose boiling points at the operating pressure are 319.41 K and 349.9 K respectively. For the top condenser, (B. deep well water) is recommended as the coolant.