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问题 问答题

实验室常用H2O2和MnO2的混合物来制取氧气，写出该反应的化学方程式______．

某化学兴趣小组的同学，已经知道MnO2在氯酸钾分解的反应中也起催化剂的作用，他们想研究氧化铁能否在该反应中起同样的作用，于是他们对该问题进行了探究．

（一）通过查阅有关资料得到以下信息：

（1）氧化铁是一种难溶于水的红棕色固体；氯酸钾和氯化钾都是极易溶于水的固体．

（2）氧化铁可以与稀盐酸反应，得到棕黄色的氯化铁溶液，这是氧化铁的化学性质之一．

（二）实验报告：

实验步骤简答
（1）称取12.25克KClO3，加热至O2不再产生为止，用去20分钟，得到4.8克O2．写出方程式______
（2）取A克氧化铁加热，没有得到O2．氧化铁的化学式为______
实验步骤简答
（3）将12.25克KClO3和A克氧化铁 混合物，加热至O2不再产生为止，用去8分钟，得到4.8克O2．反应中氧化铁的作用是______，生成氧气的质量为______．
（4）将步骤（3）试管内残余的固体进行分离，主要操作步骤有______、______和______．得到氧化铁的质量为______克．可知反应前后氧化铁的______保持不变．
（5）再将步骤（4）得到的氧化铁放入盛有足量稀盐酸的烧杯里，发现氧化铁消失，逐渐形成棕黄色溶液．实验说明分离后得到的氧化铁的______也保持不变．
（三）结论：氧化铁在氯酸钾分解的反应中也起到催化剂的作用．

答案

根据实验室常用H2O2和MnO2的混合物来制取氧气，该反应的化学方程式：2H2O2

 MnO2 
.
 
 2H2O+O2↑；

（一）通过查阅有关资料得到以下信息：

（1）氧化铁是一种难溶于水的红棕色固体；氯酸钾和氯化钾都是极易溶于水的固体．

（2）氧化铁可以与稀盐酸反应，得到棕黄色的氯化铁溶液，这是氧化铁的化学性质之一．

（二）实验报告：

实验步骤简答
（1）称取12.25克KClO3，加热至O2不再产生为止，用去20分钟，得到4.8克O2．写出方程式2KClO3
  △  
.
 
2KCl+3O2↑
（2）取A克氧化铁加热，没有得到O2．氧化铁的化学式为Fe2O3 
反应中氧化铁的作用是催化剂，生成氧气的质量为4.8克．
（4）将步骤（3）试管内残余的固体进行分离，主要操作步骤有溶解、过滤、蒸发．得到氧化铁的质量为A克．可知反应前后氧化铁的质量保持不变．
（5）再将步骤（4）得到的氧化铁放入盛有足量稀盐酸的烧杯里，发现氧化铁消失，逐渐形成棕黄色溶液．实验说明分离后得到的氧化铁的

化学性质也保持不变．

故答案为：2H2O2
 MnO2 
.
 
 2H2O+O2↑
实验步骤简答
2KClO3
  △  
.
 
2KCl+3O2↑
Fe2O3 
催化剂，生成氧气的质量为4.8克．
溶解、过滤、蒸发．得到氧化铁的质量为A克．质量
化学性质

阅读理解
任务型阅读。
     请认真阅读下列短文，并根据所读内容在文章后表格中的空格里填入最恰当的单词。
注意：每空格1个单词。
     Teamwork is just as important in science as it is on the playing field or in the gym. Scientific investigations (调查) are almost always carried out by teams of people working together. Ideas are shared, experiments are
designed, data are analyzed, and results are evaluated and shared with other investigators. Group work is
necessary, and is usually more productive than working alone.
      Several times throughout the year you may be asked to work with one or more of your classmates.
Whatever the task your group is assigned, a few rules need to be followed to ensure a productive and
successful experience.
     What comes first is to keep an open mind, because everyone's ideas deserve consideration and each group
member can make his or her own contribution. Secondly, it makes a job easier to divide the group task among
all group members. Choose a role on the team that is best suited to your particular strengths. Thirdly, always
work together, take turns, and encourage each other by listening, clarifying, and trusting one another. Mutual
support and trust often makes a great difference.
     Activities like investigations are most effective when done by small groups. Here are some more suggestions for effective team performance during these activities: Make sure each group member understands and agrees
to the task given to him or her, and everyone knows exactly when, why and what to do; take turns doing
various tasks during similar and repeated activities; be aware of where other group members are and what they
are doing so as to ensure safety; be responsible for your own learning, though it is by no means unwise to
compare your observations with those of other group members.
     After you've completed a task with your team, make an evaluation of the team's effectiveness-the strengths and weaknesses, opportunities and challenges.
TitleWorking together
ThemeEffective performance needs highly cooperated   1   .
ImportanceGroup work is necessary, and is often more productive than working   2  your own.
General rules needing    3   Keep an open mind to everyone's  4  . Divide the group task among group members.   5    and trust each other.
  6    Understand and agree to the  7    task of one's own. Do various tasks in  8  . Show concern for others to ensure safety. Take   9   for one's own learning. Compare your own observations with those of others.
Evaluating effectiveness Analyze the   10   and weaknesses. Find out the opportunities and challenges.
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汽轮机组主要有哪些项目的试验？
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