问题 选择题

下列有关化学反应热的描述中,正确的是                             (    )

①化学反应过程中一定有能量变化;②△H>0表示放热反应,△H<0表示吸热反应;③△H的大小与热化学方程式中的化学计算数成正比;④放热反应在常温下就一定能进行;⑤生成物的总能量小于反应物总能量时,△H<0;⑥化学反应中放出的热才是反应热;

A.①③⑤    

B.②④⑥    

C.①②③    

D.④⑤⑥

答案

答案:A

化学变化的特征之一就是伴随能量的变化。△H>0表示吸热反应,△H<0表示放热反应。在热化学方程式中物质前面的化学计量数表示的是参加反应的物质的物质的量,与反应热成正比。反应条件与反应是放热反应还是吸热反应无关。生成物的总能量小于反应物的总能量,反应是放热反应,△H<0。在化学反应过程中放出或吸收的能量都是反应热。答案是A。

单项选择题
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Le Trung, 33,has spent £14,000 creating Aiko,who he describes as“in her 20s”with a 32,23,33 figure,shiny hair and delicate features.

She can speak English and Japanese and is so good at mathematics that she can do Mr.Trung's accounts.

Mr.Trung,from Brampton in Ontario,Canada,said he has never had time to find a real partner,so he designed and created his ideal woman using the latest technology.

The former software programmer has taken out credit cards and loans,sold his car and spent his life savings on perfecting his“fem­bot”.

Now he is desperate to find a corporate sponsor(资助者)to help him complete and perfect Aiko.

He said,“Aiko is what happens when science meets beauty.”

"I want to make her look,feel and act as human as possible so she can be the perfect companion."

"I talk to her a lot,and hope to improve her knowledge."

"So far she can understand and speak 13,000 different sentences in English and Japanese,so she's already fairly intelligent."

"Aiko recognize faces and says hello when any of my family come around to visit. She helps me pick what to have for dinner and knows what drinks I like."

"She even helps me with directions when we're going somewhere."

"When I need to do my accounts,Aiko does all the maths. She is very patient and never complains."

"She doesn't need holidays,food or rest and she will work almost 24­hours a day. She is the perfect woman."

Mr.Trung has designed Aiko with a touch­sensitive face and body so she reacts in a natural way if she is shown affection or hurt.

He said,"She has all senses except for smell."

小题1:Why did Le Trung spend much money creating Aiko?

A.Because he prefers Aiko to a real person.

B.Because he is too busy to find a partner.

C.Because he thinks Aiko is very beautiful.

D.Because he thinks Aiko is worth much money.小题2: According to the passage,what is Aiko?

A.Aiko is a female person.

B.Aiko is Mr.Trung's girl friend.

C.Aiko is a robot that looks like a beautiful woman.

D.Aiko is a perfect woman.小题3: Aiko can do the following things EXCEPT ________.

A.that she can understand and speak English and Japanese

B.that she can do maths questions very well

C.that she can smell the strange smell

D.that she can help to receive some familiar guests小题4:What is the main idea of the passage?

A.The reason for Le Trung creating Aiko.

B.The introduction to a new scientific product-Aiko.

C.Aiko's ability or functions.

D.The process of making Aiko.