问题 选择题

近年来,随着互联网和计算机信息技术的发展,网购日渐成为人们购物的新时尚。这说明[ ]

①生产决定消费的方式 ②生产决定消费的质量和水平 ③居民的购买力不断提高 ④居民的消费结构不断优化

A.①③

B.①②

C.②④

D.③④

答案

答案:B

实验题

实验室用稀硝酸与铜反应来制备NO气体,如果采用(Ⅰ)装置(烧瓶内加入稀硝酸和铜片,必要时可加热),实验效果不十分理想,因为从观察到的现象不能有力证明反应产物是NO;有人设计了(Ⅱ)装置(橡皮塞下端连有铜丝圈),用来做该实验可以达到满意的效果。根据要求回答下列问题:

(1)用Ⅰ装置做实验时,实验过程中由于观察到烧瓶内有             现象,而不能有力证明反应产物是NO;收集NO能否用瓶口向上排空气法?答:     (填“能”“否”)。

(2)用Ⅱ装置做实验时,将有关操作补充完全:

①将分液漏斗的活塞打开,从U形管的B侧管口注入稀硝酸,一直注到       为止。

a.刚好浸没铜丝下端   b.刚好浸没铜丝中部   c. 单孔塞下沿与液面间不留有空隙

②关闭活塞,用酒精灯对U形管的A侧加热,当        时,撤去酒精灯。

(3)在(2)的实验中:

①什么情况下反应自动停止?                                         。

何处观察到无色的NO气体?                                         

②如果再将分液漏斗的活塞慢慢打开,可在分液漏斗中观察到哪些明显现象?

答:                                                                 。

阅读理解

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