问题 选择题

下列区分两种不同物质的方法不合理的是

A.用燃着的木条区分空气与二氧化碳

B.用肥皂水区分硬水与软水

C.用水区分CuO粉末与MnO2粉末

D.用酚酞试液区分纯碱溶液与盐酸

答案

答案:C

分析:二氧化碳不能燃烧,也不支持燃烧.硬水中含有较多的钙离子、镁离子,这些两种能和肥皂水反应生成不溶于水的物质.氧化铜和二氧化锰都是不溶于水的固体.纯碱是碳酸钠,碳酸钠溶液显碱性.稀盐酸显酸性.

解答:解:A、二氧化碳能使燃烧的木条熄灭,空气不能使燃烧的木条熄灭.故选项错误;

B、加入肥皂水产生泡沫较多的是软水,产生泡沫较少的是硬水.故选项错误;

C、氧化铜和二氧化锰都是不溶于水的黑色粉末,用水无法区分.故选项正确;

D、纯碱能使酚酞试液变红色,盐酸不能使酚酞变色.故选项错误.

故选C.

填空题
阅读理解

In a country that defines itself by ideals, not by shared blood, who should be allowed to come to work and live here? In the wake of the Sept.11 attacks these questions have never seemed more pressing.

On Dec.11, 2001, as part of the effort to increase homeland security, federal and local authorities in 14 states staged “Operation Safe Travel”---raids on airports to arrest employees with false identification.In Salt Lake City there were 69 arrests.But those captures were anything but terrorists, most of them illegal immigrants from Central or South America.Authorities said the undocumented workers’ illegal status made them open to blackmail(讹诈)by terrorists.

Many immigrants in Salt Lake City were angered by the arrests and said they felt as if they were being treated like disposable goods.Mayor Anderson said those feelings were justified to a certain extent.“We’re saying we want you to work in these places, we’re going to look the other way in terms of what our laws are, and then when it’s convenient for us, or when we can try to make a point in terms of national security, especially after Sept.11, then you’re disposable.They are whole families being uprooted for all of the wrong reasons,” Anderson said.

If Sept.11 had never happened, the airport workers would not have been arrested and could have gone on quietly living in America, probably indefinitely.Ana Castro, a manager at a Ben & Jerry’s ice cream shop at the airport had been working 10 years with the same false Social Security card when she was arrested in the December airport raid.Now she and her family are living under the threat of deportation(驱逐出境).Castro’s case is currently waiting to be settled.While she awaits the outcome, the government has granted her permission to work here and she has returned to her job at Ben & Jerry’s.

小题1:How did the immigrants in Salt Lake City feel about “Operation Safe Travel”?

A.Guilty

B.Offended

C.Disappointed

D.Discouraged小题2:Undocumented workers became the target of “Operation Safe Travel” because ____.

A.evidence was found that they were potential terrorists

B.most of them worked at airports under threat of terrorists

C.terrorists might take advantage of their illegal status

D.they were reportedly helping hide terrorists around the airport小题3:By saying “…we’re going to look the other way in terms of what our laws are”, Mayor Anderson means “______”.

A.there are other ways of enforcing the law

B.we will examine the laws in a different way

C.we will turn a blind eye to your illegal status

D.the existing laws must not be ignored