问题 问答题

根据实验室制取氯气的装置图,请回答:

(1)仪器A的名称是______,反应前仪器A中加入的固体试剂为(写化学式)______;

(2)图中氯气的收集方法应该是______,烧杯中氢氧化钠溶液的作用是______.

(3)若将润湿的淀粉KI试纸放入收集氯气的集气瓶中,可以观察到试纸变蓝的现象,氯气和KI溶液生成碘单质的离子方程式为______.

答案

(1)实验室制取氯气用浓盐酸和二氧化锰在加热条件下制取,反应的化学方程式为MnO2+4HCl(浓)

.
MnCl2+Cl2↑+2H2O,为固体和液体的反应,仪器A圆底烧瓶放MnO2,长颈漏斗放浓盐酸,

故答案为:圆底烧瓶;MnO2

(2)氯气的密度比空气的大,可用向上排空气收集,又由于氯气有毒,还要防止氯气污染空气,氯气和氢氧化钠反应生成氯化钠、次氯酸钠和水,所以烧杯中氢氧化钠溶液的作用是吸收多余的氯气,防止污染,

故答案为:向上排空气法;吸收多余的氯气,防止污染;

(3)氯气具有氧化性,能将碘离子氧化为碘单质,发生的反应是:Cl2+2I-=2Cl-+I2,故答案为:Cl2+2I-=2Cl-+I2

判断题
阅读理解

The British are the most voracious(如饥似渴的) newspaper readers in the world.

They read newspapers at breakfast ; they walk to the bus reading a newspaper; they read a newspaper on bus, as they go to work; and on the way back home, after work, they are engaged in reading an evening newspaper.

There are many" morning papers", both national and provincial. The most famous is The Times. Different from what many foreigners believe, this is not a government newspaper. The various newspapers usually have their own views of the Communist Morning Star. The Labor Party and the Trades Union Congress no longer have a daily newspaper to represent them.

Bold headlines and a variety of photographs are features of the British press. Some newspapers, such as the sober Daily Telegraph and The Times, use photographs sparingly(节省). The more“popular”newspapers, using the small or "tabloid"(小报) format, such as the Daily Express, the Mail, the Daily Mirror and the Sun, use pictures extensively and also run strip cartoons and humorous drawings, some of which present striking pictorial comment on politics.

Besides offering features common to newspapers all over the world, British newspapers specialize in pages devoted to criticism of the arts and a woman's page. One feature found in many foreign newspapers is missing in British papers:the serial(连载).

Nearly all papers pay special attention to the reporting of sports and athletics. The evening newspapers are often bought because the buyer wants to know the winner of a race, or to get good tip for a race that is still to be run. There is no censorship(审查) of the press in Britain (except in wartime), though of course all newspapers—like private persons—are responsible for what they publish, and can be sued for libel (为诽谤而被起诉) for publishing articles that go beyond the bounds of decency(正派), or for ignorance of court”. (e.g. calling a man a murderer while he is still being tried.Such cases are not often)

1.Which of the following does NOT serve as an evidence(证据) that the British are the great newspaper readers?

A.They read newspapers at breakfast.       B.They read newspapers at work.

C.They read newspapers on bus.           D.They read newspapers on the way back home.

2.Many of foreigners think that_______.

A.The Times is an organ (喉舌) of the government

B.The Times has its own views on politics

C.The Times is the most famous newspaper in the world

D.The Times pays too much attention to the reporting of political events

3.British newspapers are characterized by ________.

A.bold headlines                       B.various kinds of photographs

C.striking pictorial comment on politics      D.both A and B

4.Which of the following conclusions can NOT be drawn from the passage?

A.Englishmen always take every possible chance to read newspapers.

B.In Britain, newspapers must be carefully examined by the authorities(当局) before their publication for fear that they present anything offensive.

C.Few British newspapers publish libelous articles.

D.The Times is one of the world-famous newspapers.