实验课上,老师给同学们提供了下列仪器以及大理石、氯酸钾、二氧化锰三种药品. (

题型:问答题

问题:

实验课上,老师给同学们提供了下列仪器以及大理石、氯酸钾、二氧化锰三种药品.

(1)利用老师提供的仪器和药品可以制取氧气,写出相应反应的化学方式______.检验制取的气体是否为氧气的方法是______.

(2)若要制取一瓶二氧化碳气体.同学们还需向老师领取的药品是______ (填名称),制取二氧化碳时,上述仪器中一定不会用到的是______   (填序号).

考点:氧气的制取和收集二氧化碳的制取和收集实验室制取和收集气体的思路化学反应方程式的书写文字表达式
题型:问答题

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。

Recently some American scientists have given a useful piece of advice to people in industrialized nations.They say people should eat more of the same kind of food eaten by humans living more than 10,000 years ago.小题1:  

The scientists say that the human life has changed greatly.Our bodies have not been able to deal with these changes in lifestyle and this had led to new kinds of sicknesses.  小题2:  So they are called "diseases of civilization".Many cancers and diseases of the blood system are examples of such diseases.

Scientists noted that people in both the Old Stone Age and the New Stone Age enjoyed very little alcohol or tobacco, probably none. 小题3:  However, a change in food is one of the main differences between life in ancient times and that of today.

Stone Age people hunted wild animals for their meat, which had much less fat than domestic ones.They ate a lot of fresh wild vegetables and fruits.They did not have milk or any other dairy products, and they made very little use of grains. 小题4:  We eat six times more salt than our ancestors.We eat more sugar.We eat twice as much fat but only one third as much protein and much less vitamin C.

 小题5: But scientists say that we would be much healthier if we eat much the same way the ancient people did, cutting the amount of fatty, salty and sweet food.

A.Stone Age people lived a simple life.

B.But today, we enjoy eating a lot of these.

C.In that case, they would live much healthier.

D.Ancient people also got lots of physical exercise. E.These new sicknesses were not known in ancient times.

F.People today probably don't want to live like our ancestors.

G.Modern people used to suffer from "diseases of civilization".

题型:问答题

根据前后学习的难度差异,可以把迁移分为__________和________。

题型:问答题

下列哪些费用的缴纳期限和申请费不同?()

A.优先权要求费

B.申请附加费

C.发明专利申请的公布印刷费

D.发明专利申请的实质审查费

题型:问答题

伤寒患者排菌最多的时期是()

A.起病后第1周

B.起病后第2~4周

C.起病前1周

D.起病后第5周

E.起病后第6周

题型:问答题

消毒和灭菌的定义?

更多题库