问题 选择题

向平底烧瓶中放入氢氧化钡晶体[Ba(OH)2·8H2O]和氯化铵晶体,塞紧瓶塞。在瓶底和木板间滴少量水,如图所示。一会儿,就会发现瓶内固态物质变稀,有液体生成,瓶壁变冷,小木板上因少量水结冰冻结,而被烧瓶黏住,这时打开瓶塞,散发出来的气体有氨味。这是自发地发生了反应:Ba(OH)2·8H2O(s)+2NH4Cl(s)===BaCl2(s)+2NH3(g)+10H2O(l)。实验中的下列结论正确的是(  )

A.自发反应一定是放热反应

B.自发反应一定是吸热反应

C.有的吸热反应也能自发进行

D.吸热反应不能自发进行

答案

答案:C

焓变小于0利于自发;熵变大于0利于自发;判断某一反应能否自发不能孤立的看焓判据或熵判据,要综合这两个判据,即根据自由能变判断:△G=△H+T△S;若△G<0反应一定能自发;若△G>0反应一定不能自发;

阅读理解

One silly question I simply can’t stand is “How do you feel?” Usually the question is asked of a man in action — a man on the go, walking along the street, or busily working at his desk. So what do you expect him to say? He’ll probably say, “Fine, I’m all right,” but “you’ve put a bug in his ear” — maybe now he’s not sure. If you’re a good friend, you may have seen something in his face, or his walk, that he overlooked that morning. It starts him worrying a little. First thing you know, he looks in a mirror to see if everything is all right, while you go merrily on your way asking someone else, “How do you feel?”

Every question has its time and place. It’s perfectly acceptable, for instance, to asked “How do you feel?” if you’re visiting a close friend in the hospital. But if the fellow is walking on both legs, hurrying to catch a train, or sitting at his desk working, it’s no time to ask him that silly question.

When George Bernard Shaw, the famous writer of plays, was in his eighties, someone asked him, “How do you feel?” Shaw put him in his place. “When you reach my age,” Shaw said, “either you feel all right or you’re dead.”

26. The passage tells us that some greetings such as “How do you feel?” __________.

A. show one’s consideration for others     

B. are a good way to make friends

C. are proper to ask a man in action       

D. generally make one feel uneasy

27. The question “How do you feel?” seems to be correct and suitable when asked of _________________________.

A. a man working at his work                 B. a person having lost a close friend

C. a stranger who looks somewhat worried   D. a friend who is ill

28. The writer seems to feel that a busy man should _________________.

A. be praised for his efforts             

B. never be asked any questions

C. not be troubled                    

D. be discouraged from working so hard

29. “You’ve put a bug in his ear” means that you’ve _________________.

A. made him laugh merrily              

B. given him some kind of warning

C. shown much concern for him          

D. played a joke on him

30. George Bernard Shaw’s reply in the passage shows his __________.

A. cleverness         B. cheerfulness              C. power and skills        D. politeness                          

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