问题 填空题

钢铁是人类生活和生产中非常重要的材料,但全世界每年都有约占产量四分之一的钢铁生锈损失。通过查阅资料、进行实验对上述问题进行研究。

请回答下列问题:

⑴工业上用一氧化碳和赤铁矿(主要成分是Fe2O3)炼铁化学方程式是

                                                             

⑵常温下,铁生锈的条件是铁接触空气中的                    

⑶多数食品容易吸收空气中的水分变潮湿,并吸收空气中的氧气而腐败。生产上多在食品中放入一小包CaO粉末。可使食品保持干燥;现已研究成功在食品中放入一小包铁粉(包裹在多孔泡沫塑料袋中),铁粉吸收水分和氧气,变为铁锈。用铁粉代替CaO粉末的优点是                                                      

                                                       

答案

⑴3CO+Fe2O3高温 2Fe+3CO2

⑵H2O    O2

⑶铁粉吸收水分和氧气,不仅使食品保持干燥而且防止食品被氧化变质

(回答合理即给分)

(1)炼铁的原理是用一氧化碳和赤铁矿在高温的条件下反应生成铁和二氧化碳;

故答案为:Fe2O3+3CO高温2Fe+3CO2

(2)铁在同时接触到水和氧气时才会被锈蚀,因此铁生锈的条件应是铁接触空气中的水和氧气,可以把一支铁钉的一半浸入试管的蒸馏水中,观察生锈情况,

故答案为:H2O;O2

(3)铁粉既可吸收水份防止食品潮解,又可吸收氧气防止食品腐败,而CaO只能吸收水分而防止食品潮解,

故答案为:铁粉吸收水分和氧气,不仅使食品保持干燥而且防止食品被氧化变质

完形填空

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?  71  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?"

  72  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.  73 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.  74  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.  75 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.

问答题 简答题