问题 问答题

现有下列A、B、C、D、E五种实验装置.

(1)甲同学用过氧化氢溶液与二氧化锰制取氧气.写出该反应的文字表达式(或用符号表达式)______,二氧化锰起______作用.

(2)乙同学用高锰酸钾制取氧气时出现下列现象,请你帮他分析出现下列现象的原因.

①加热一段时间没有气泡,______.②试管破裂______.

(3)氨气是一种极易溶于水,且密度比空气小的气体,这是氨气的______(选填“物理”或“化学”)性质,所以收集氨气最好用______装置(所选装置用序号填空).丙同学在实验室用加热固体硫酸铵和固体熟石灰的混合物来制取氨气,所以应用的发生装置是______.

答案

(1)用过氧化氢溶液与二氧化锰制取氧气时产生水和氧气,反应的方程式为:2H2O2

 MnO2 
.
 
2H2O+O2↑;其中二氧化锰做催化剂,起催化作用;

(2)用高锰酸钾制取氧气时,①加热一段时间没有气泡,可能是装置漏气;②试管破裂,可能原因有:加热前没有给试管预热,受热不均匀;试管外壁有水,加热时没擦干;试管接触到灯芯;试管口部高于试管底部,导致冷凝水倒流炸裂试管等;

(3)氨气是一种极易溶于水,且密度比空气小的气体,溶解性和密度属于物理性质;收集时只能用向下排空气法来收集,应选择E;用加热固体硫酸铵和固体熟石灰的混合物来制取氨气,根据题意可知应选择固体加热装置,则选A装置符合.

故答案为:(1)2H2O2

 MnO2 
.
 
2H2O+O2↑;催化;

(2)装置漏气;加热前没有给试管预热等;

(3)物理;E;A.

阅读理解

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

If you are hungry, what do you do? Have your favorite meal and stay quiet after that? 小题1:  But it never lets you know, because you keep it busy thinking about your friends or favorite stars.So it silently serves your needs and never lets itself grow.When mind loses its freedom to grow, creativity gets a full stop.This might be the reason why we all sometimes think "What happens next?", "Why can't I think?"

 小题2: Why reading but not watching TV? It is because reading has been the most educative tool used by us right from childhood.Since it develops other aspects of our life, we have to get help from reading.

Once you read a book, you run your eyes through the lines and your mind tries to explain something to you. 小题3:Now this seed is unknowingly used by you to develop new ideas.If it is used many times, the same seed can give you great help to relate a lot of things which you would have never thought of in your wildest dreams!

This is nothing but creativity. 小题4: Within no time you can start talking with your friends in English or any other language and never run out of the right words.

So guys, do give food for your thoughts by reading, reading and more reading. 小题5:Go and get a book!

A.The interesting part of the book is stored in your mind as a seed.

B.Why not do some reading while you are hungry?

C.Just like your stomach, your mind is also hungry.

D.Now what are you waiting for? E.Hunger of the mind can be actually solved through wide reading.

F.Reading can help you make more friends, too.

G.Also this makes a significant contribution to your vocabulary.

单项选择题 B1型题