如图,将一锌片放入1mol•L-1蓝色Cu(NO3)2溶液中,观察到下列实验现象

题型:问答题

问题:

如图,将一锌片放入1mol•L-1蓝色Cu(NO32溶液中,观察到下列实验现象:①反应初期锌片上有大量气泡冒出,同时液面的上一层Cu(NO32溶液开始呈现绿色,并且逐渐向液面下的深处扩散,试管底部有红色固体出现.②与锌片接触的溶液温度明显升高,反应越来越剧烈,并在红色固体上方开始出现一层蓝色沉淀,并逐渐增多.③反应后期溶液逐渐变为无色,试管底部又有部分白色沉淀物.

回答下列问题:

(1)反应结束时,试管底部存在的一些蓝色沉淀是什么物质______,白色沉淀可能是什么物质______,用离子方程式表示实验中观察到的红色固体产生的原因______.

(2)有学生甲认为,反应中产生的大量气泡可能是氢气,支持这种说法的理由是______.

(3)学生乙将反应过程中产生的气体用排水法收集起来,这是一种无色气体,用爆鸣法测试不能产生爆呜声,则学生甲的假设被推翻.学生乙又对这种无色气体进行推测,并设计了一个简便的实验方法证实了他的推测,写出学生乙推测出的这种气体的分子式______;验证该气体的实验方法是______.

(4)学生丙解释反应速率逐渐加快的原因时,认为除温度升高外还有一个重要因素,请问是什么因素?______.

(5)起初实验小组同学认为,溶液显绿色可能是Zn(NO32溶液的颜色,但学生丁将Zn(NO32固体溶于水后却得到无色溶液,他马上回想起该溶液的颜色与浓硝酸和铜片反应后的溶液颜色极为相似,于是他又提出了关于溶液呈绿色的一种新的假设:可能是硝酸铜溶液中溶入了一种气体,这种气体可能是______,请设计一个简单的实验验证这种假设正确与否______.

考点:单质铜氧化亚铜氧化铜氢氧化铜化学科学探究
题型:问答题

春秋初期,楚国君主首先称王。随后,吴、越等国国君也相继称王。上述现象本质上反映  [ ]

A.专制制度动摇

B.江南经济超过北方

C.分封制的动摇

D.周王至尊地位动摇

题型:问答题

统计的特点包括( )。

A.总体性

B.变动性

C.数量性

D.具体性

E.稳定性

题型:问答题

大肠杆菌中,任何由于DNA损伤造成的DNA复制障碍都会诱导()的信号,即允许跨过障碍进行复制,给细胞一个生存的机会。

题型:问答题

Are you one of those who always fear whenever a dog is approaching If you are, you have got phobia ( a very p feeling of being afraid of something ). Of all human fears, phobias may be the most uncontrollable. They are most often caused by a particular situation or object. In general, pho- bias can mainly be divided into three varieties. To begin with, agoraphobia is a fear of staying in strange surroundings, for example, an unfamiliar place, or an open area. Social phobia refers to the anxiety people show when they have to stay or perform on social events, for instance, speaking in front of the class. Lastly, there are a wide range of specific phobias. People suffering from this kind of phobia are terrified of specific objects or creatures, such as spiders, perhaps to your surprise, clowns. Besides, there are about six hundred and fifty phobias listed by psychologists (心理学家) as yet.
Faced with their phobias, many people choose to do nothing but just escape the situations or objects they fear. Psychologists, however, warn that if not treated properly, this kind of anxiety will get worse, so that it may disturb the sleep pattern, cause physical symptoms, and finally affect their daily activities. As for treatment, clinical research has discovered that medicine for anxiety is not successful in curing phobias. However, the anxiety disorders can be efficiently treated through cognitive behavioral therapy (认知行为疗法) , through which patients are led to inspect the connections between their own fear and the situation or object, and then actively choose the acceptable treatments. Also, other treatments proved effective in reducing phobias are meditation, listening to calming music, and so on.

What do those with agoraphobia feel terrified of and anxious about

A.Staying on a square.

B.Touching insects, like spiders.

C.Being harmed by viruses.

D.Giving a speech in presence of many peopl

题型:问答题

两株高茎豌豆杂交,后代既有高茎又有矮茎,让高茎豌豆全部自交,则自交后代性状分离比为()

A.3∶1

B.1∶1

C.9∶6

D.5∶1

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