问题 实验题

为了验证铁与水蒸气可以反应,某校化学兴趣小组根据下图所示装置进行实验。

(1)这套装置主要包括水蒸气发生、水蒸气与铁粉反应、 ____等三部分。

(2)仪器A的名称是____。

(3)该装置检验气密性的方法是___。

(4)大试管底部湿棉花的作用是____。

(5)大试管中发生反应的化学方程式为____。

答案

(1)检验气体成分

(2)铁架台

(3)将导管下端浸入水中,微热试管,导管口有气泡冒出;冷却,导管口又形成一段水柱,则证明装置气密性良好

(4)受热产生水蒸气

(5)3Fe+4H2O(g)Fe3O4+4H2

单项选择题
单项选择题

A child may lean against a doorpost with his or her arms folded. To the onlooker, it may look like a benign posture—however, there may be a victimized child who understands that this is the bully’s "shorthand" code of conveying the message: "Hand me your lunch as you walk by me, or else."

Bullying may be expressed in many forms. Boys are generally targeted more than girls. Boys tend to use physical aggression when they bully .by hitting, kicking, and fighting. Girls, on the other hand, more often use exclusionary techniques to bully—a form of aggression often referred to as relational aggression. Girls often start rumors, form cliques to keep certain people out, and ignore other children in attempts to show dominance over another child.

Many children who are victimized fit into one of two types: the passive victim, and the provocative victim. While people often feel bad about passive victims, provocative victims often elicit less compassion from others. Sometimes it appears that the provocative victim has "brought on" his or her own fate—but does any child deserve to be the target of repeated physical or verbal aggression Why might so-called provocative victims actively participate in being the target of bullying: For example, are their provocative gestures simply a clumsy way of attempting to interact with others One feels compassion for the inhibited child because he is reserved; a social misfortune in our society, but an aggressive child is given none of this.

The dynamics of the bully/victim relationship need to be understood in a larger context (Pepler, Craig & O’Connell, 1999). It is not only the bully and the victim that is involved in a system of interaction: The bullying context includes multiple levels of the child’s social environment. The bully may enlist the help of "henchmen" (those who assist the bully, but often do not have the initiative or leadership to initiate bullying). Also, bystanders (whether actively encouraging the bullying act or passively standing by) play a role in maintaining the pattern of bullying. Even the students who habitually flee the site of a bullying act play a role in maintaining the bully/victim interaction.

In handling the situation, it is important not to focus only on the one or two students that are directly involved, but on the playground and school as a whole. Studies have shown that in order to break down the stability of peer bullying you must initiate change on many levels: Not only in teaching the bullied child how to assert himself or herself and to deflect attacks, but also to raise awareness about the problem of bullying and encourage the school community at large to take a united stance against bullying.

The word "exclusionary" ( Line 3, Para. 2) can be best explained by ().

A.not allowing someone to take part in something

B.using behaviors intended to hurt other people physically

C.tending to accept things that happen without taking any action

D.doing something in a deliberate manner and intended to cause harm