问题
选择题
250℃和1.01×105Pa时，反应2N2O5（g）═4NO2（g）+O2（g）△H=+56.76kJ/mol，自发进行的原因是（ ）
A．是吸热反应
B．是放热反应
C．熵增效应大于能量效应
D．是熵减反应
答案
反应能自发进行，应有△G=△H-T•△S＜0，因△H＞0，则△H＜T•△S，说明取决于焓变和熵变的综合判据，
故选C．
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250℃和1.01×105Pa时，反应2N2O5（g）═4NO2（g）+O2（g）△H=+56.76kJ/mol，自发进行的原因是（ ）
A．是吸热反应
B．是放热反应
C．熵增效应大于能量效应
D．是熵减反应
反应能自发进行，应有△G=△H-T•△S＜0，因△H＞0，则△H＜T•△S，说明取决于焓变和熵变的综合判据，
故选C．
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| Middle school days are both fun and busy. Students spend their days in class, listening to the interesting and 1 boring words of the teacher. They spend the short breaks running, playing, and shouting happily 2 going back to the classroom again. But 3 should students spend their free time outside school? In Western countries, it is ordinary for students to have a part-time job after school. And at weekends students can make their own money and learn more about the " 4 world". They enjoy the independence (独立) and (of course) money, and parents enjoy the quiet house. 5 , it seems that, in China, parents 6 so much about their children's studies that they would prefer to see their children 7 . most of their free time studying and preparing for all those exams. It is natural for 8 to feel that way in China, but I believe the answer lies in balance (平衡). Sometimes, Western school children work long hours after school to make money, and so they become too tired to listen in class or have no time for homework. But Chinese students spend 9 much time on their studies that all else becomes less important until they want that new MP4 player. So, find a good and healthy balance! If you have a part-time job, you'll be 10 , and your parents will also be happy because you're spending the money you make and not theirs! | ||||
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