问题 填空题

某学生利用以下装置探究纯净干燥的氯气与氨气之间的反应.

回答下列问题:

(1)根据下列所给试剂,选择制取氨气的装置是(填对应字母)______;写出制备氯气的离子反应方程式______.

二氧化锰、碱石灰、浓盐酸、浓氨水、烧碱、生石灰

(2)已知,E装置是用于使纯净干燥的氯气与氨气发生反应的装置,试说明该装置的设计意图:______.

(3)根据实验目的,所选装置的连接顺序为(填装置的接口字母):______接______,______接( f ),( g )接______,______接______,______接______;其中,G装置的作用是______.

(4)氯气和氨气在常温下相混合就会发生反应生成氯化铵和氮气,该反应的化学方程式为:______;其中,氧化剂与还原剂的物质的量之比是______.

(5)请你评价此套装置有何缺点______.

答案

(1)根据提供的药品,应用浓氨水和碱石灰或生石灰反应制备氨气,可用A装置,实验室用二氧化锰和浓盐酸反应制备氯气,反应的离子方程式

为MnO2+4H++2C1-

  △  
.
 
Mn2++C12↑+2H2O,故答案为:A; MnO2+4H++2C1-
  △  
.
 
Mn2++C12↑+2H2O;

(2)由于氨气的密度小,氯气的密度大,密度小氨气的从长管进入向上扩散,密度大的氯气从短管进入向下扩散,这样能较快的充分的混合,具体操作为将比空气轻的氨气从长管口f进入,比空气重的氯气从短管口g进入,使反应气体逆流接触充分反应,中间导管用于排出空气以减少内部压力,

故答案为:将比空气轻的氨气从长管口f进入,比空气重的氯气从短管口g进入,使反应气体逆流接触充分反应,中间导管用于排出空气以减少内部压力;

(3)装置A制取氨气,可用浓氨水与碱石灰(或烧碱或生石灰等),B装置中盛放的碱石灰,用来干燥氨气;G装置中盛放的饱和食盐水,用来除去氯气中混有的氯化氢气体;F装置用来干燥氯气,然后在E中混合反应,则连接顺序为a接d,e接f,g接h,i接j,k接b,

故答案为:a;d;e;h;i;j;k;b;除去C12中的HCl气体;

(4)氯气和氨气在常温下相混合就会发生反应生成氯化铵和氮气,反应的化学方程式为3C12+8NH3=6NH4Cl+N2,由化合价的变化可以看出,当3mol氯气参加反应时,有2mol氨气被氧化,所以氧化剂和还原剂的物质的量之比为3:2,

故答案为:3C12+8NH3=6NH4Cl+N2;3:2;

(5)氯气和氨气都污染空气,不能直接排放到空气中,实验缺少尾气处理装置,

故答案为:缺少尾气处理装置,造成空气污染.

填空题
单项选择题


The sun today is a yellow dwarf star. It is fueled by thermonuclear reactions near its center that convert hydrogen to helium. The sun has existed in its present state for about 4 billion, 600 million years and is thousands of times larger than the Earth.
By studying other stars, astronomers can predict what the rest of the sun’s life will be like. About 5 billion years from now, the core of the sun will shrink and become hotter. The surface temperature will fail. The higher temperature of the center will increase the rate of thermonuclear reactions. The outer regions of the sun will expand approximately 35 million miles, about the distance to mercury, which is the closest planet to the sun. The sun will then be a red giant star. Temperatures on the earth will become too hot for life to exist.
Once the sun has used up its thermonuclear energy as a red giant, it will begin to shrink. After it shrinks to the size of the earth, it will become a white dwarf star. The sun may throw off huge amounts of gases in violent eruptions called nova explosions as it changes from a red giant to a white dwarf.
After billions of years as a white dwarf, the Sun will have used up all its fuel and will have lost its heat. Such a star is called a black dwarf. After the Sun has become a black dwarf, the earth will be dark and cold. If any atmosphere remains there, it will have frozen onto the earth’s surface.

What will probably be the first stage of change as the sun becomes a red giant

A.Its core will cool off and use less fuel.

B.Its surface will become hotter and shrink.

C.It will use up its thermonuclear energy.

D.Its center will grow smaller and hotter.