问题 选择题

下列关于物质分类正确的是

A.空气是混合物,加碘盐是纯净物

B.矿泉水是混合物,蒸馏水是氧化物

C.单质都是同一种分子构成的纯净物

D.水银是混合物,干冰是化合物

答案

答案:B

考点:

专题:物质的分类.

分析:纯净物是由一种物质组成的物质,混合物是由多种物质组成的物质;由同种元素组成的纯净物是单质;由不同种元素组成的纯净物是化合物;在由两种元素组成的化合物中,其中一种是氧元素的是氧化物;据此逐项分析即可.

解答:解:A、空气中含有氮气、氧气等物质,属于混合物;加碘食盐中含有氯化钠、碘酸钾等物质,也属于混合物;故选项说法错误.

B、矿泉水中含有水、可溶性的矿物质等物质,属于混合物;蒸馏水(H2O)是由两种元素组成且有一种是氧元素,属于氧化物;故选项说法正确.

C、单质不一定都是由同一种分子构成的纯净物,如铁是纯净物,它是由铁原子直接构成的;故选项说法错误.

D、水银(金属汞)中只含有一种物质,属于纯净物;干冰(固体的二氧化碳)是由不同种元素组成的纯净物,属于化合物;故选项说法错误.

故选B.

点评:本题考查纯净物、混合物、单质、化合物的判别,了解常见物质的组成与构成、抓住各概念的特征进行分析判断是解答此类题的关键.

填空题
填空题

[A] Is that what the American viewing public is getting.’ Perhaps 10% of prime-time network programming is a happy combination of entertainment and enrichment. There used to be television-movies rich in human values,, but they have now become an endangered species. I find television too much concerned with what people have and too little concerned with who they are, very concerned with taking care of No. 1 and not at all concerned with sharing themselves with other people. All too often it tells us the half truth we wan! to hear rather than the whole truth we need to hear.

[B] Why is television not more fully realizing its humanizing potential Is the creative community at fault Partially. But not primarily. I have lived and worked in that community for 32 years, as both priest and producer. As a group, these people have values. In fact, in Hollywood in recent months, audience enrichment has become their thing. A coalition of media companies has endowed the Humanists Prize so that it can recognize and celebrate those who accomplish it.

[C] Every good story will not only captivate its viewers but also give them some insight into what it means to be a human being. By so doing, it can help them grow into the deeply centered, sovereignty free, joyously loving human being God made them to be. Meaning, freedom and love are the supreme human values. And this is the kind of human enrichment the American viewing public has a right to expect from those who make its entertainment.

[D] The problem with American TV is not the lack of storytellers of conscience but the commercial system within which they have to operate. Television in the U.S. is a business. [n the past, the business side has been balanced by a commitment to public’, service. But in recent years the fragmentation of the mass audience, huge interest payments and skyrocketing production costs have combined with the FCC’s abdication of its responsibility to protect the common good to produce an ahnost total preoccupation with the bottom line. The networks are struggling to survive. And that, the statistics seem to indicate, is mindless, heartless, escapist fare. If we are dissatisfied with the moral content of what we are invited to watch, I think we should begin by examining our own consciences. When we tune in, are we ready to plunge into reality, so as to extract its meaning, or are we hoping to escape into a sedated world of illusion And if church leaders want to elevate the quality of the country’s entertainment, they should forget about boycotts, production codes and censorship. They should work at educating their people in media literacy and at mobilizing them to support quality shows in huge numbers.

[E] It is not a question of entertainment or enrichment. These are complementary concerns and presuppose each other. The story that entertains without enriching is superficial and escapist. The story that enriches without entertaining is simply dull. The story that does both is a delight.

[F] That is the only sure way to improve the moral content of America’s entertainment.

[G] Despite questions of the motivation behind them, the attacks by the President and the Vice President on the moral content of television entertainment have found an echo in the chambers of the American soul. Many who reject the messengers still accept the message. They do not like the moral tone of American TV. In our society only the human family surpasses television in its capacity to communicate values, provide role models, form consciences and motivate human behavior. Few educators, church leaders or politicians possess the moral influence of those who create the nation’s entertainment.

Order:

[G]______→41.______→42.______→43. ______→44. ______→45.______→[F]

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