题目

--- The manager of the factory wants to improve production a great deal, but he doesn’t spend much on technology. ---I am afraid he won’t realize his dream. You know ________. A. you can’t eat your cake and have it B. empty vessels make the greatest sound C. enough is as good as a feast D. two heads are better than one 答案：A写出下列反应的化学方程式并填空．（1）实验室用过氧化氢溶液制取氧气：______：常加入的一种黑色固体的作用是______．（2）铝和稀盐酸反应：______；该反应属于______（填“放热”或“吸热”）反应．（3）炼铁厂以赤铁矿为原料炼铁：______；该反应类型______（填“是”或“不是”）置换反应．（4）铜绿受热分______；该反应类型的是______．（5）鉴别氮气和二氧化碳常用的一种溶液的名称是______，反应的化学方程式为______．