520除以5的商是14．______（判断对错）

过氧化氢很重要的研究和应用价值．

（1）实验室利用反应2H₂O₂

催化剂

2H₂O+O₂↑可制备氧气．

①取等物质的量浓度等体积H₂O₂溶液分别进行下列实验，研究外界条件对该反应速率的影响，实验报告如下表所示．

序号	条件		现象	结论
	温度/℃	催化剂
1	40	FeCl3溶液
2	20	FeCl3溶液
3	20	MnO2
4	20	无

实验1、2研究的是______对H₂O₂分解速率的影响．实验2、3的目的是______．

实验中可以表明该反应速率差异的现象是______．

②实验室用MnO₂做该反应的催化剂，使用如图所示装置的A部分制备O₂，避免反应过于剧烈的操作是______．

（2）Na₂O₂与水反应也可生成O₂．某同学取4g Na₂O₂样品与过量水反应，待反应完全终止时，得100mL溶液X和448mL O₂（已折算为标准状况）．该同学推测样品中含有杂质或反应中生成H₂O₂，并进行实验研究．

通过如图所示整套实验装置测定Na₂O₂样品的纯度，假设所含杂质不参加反应．取25mL X，滴入烧瓶内再加入过量KMnO₄酸性溶液反应，使其充分反应，最终生成56mL O₂（已折算为标准状况），则此样品中Na₂O₂的质量分数是______．

任务型阅读。

     Do you like chocolate? Maybe most people do. A box of  it can be a great gift. Buy one for a friend

and give it as a surprise. See how happy that person gets.

     Say you just got a box of   chocolate.   Which piece do you pick first ?   A man has studied people's

choices. He says they tell something about the person. Did you choose a round piece? You are a person

who likes to the party. Did  you choose an oval (椭圆形的) shape?   (1)You are a person who likes to

make things. Picking a square shape  shows something else.  The person is honest and truthful. You can

depend on (依靠) him or her.

     (2)What kind of ________ do you ________?   Maybe you like milk  chocolate.  This  shows  you

have warm feelings about the past. Dark chocolate means something else.   A  person  who chooses   it

looks toward the future. What about white chocolate?  Would you choose it? If so, you may find it hard

to make up your mind. Some people like chocolate with nuts (果仁). These are people who like to help

others.

     Different choices may show different characters(性格)．Do you believe these ideas?

     Can candy tell all these things? It doesn't   really  matter. There   is   one   sure thing about eaters of

chocolate. They eat it because they like it.

1．回答下面问题:

What kind of chocolate may a helpful man choose according to this passage?(不超过5个单词)  

   _____________________________________________________________________

2．将(1)句译成中文:_____________________________________________________

3．在(2)句的空白处填入适当的词使句意完整、上下文通顺:________,________

4．找出文中与下列句子意思相近的句子:You enjoy singing, dancing and drinking.

   _______________________________________________________________________

5. 找出文中最能表达该短文主题的句子:

____________________________________________________________________

The box is too heavy for him           .               [ ]

A. to carry        

B. to carry it            

C. carrying

仓库选择地点应与周围的其他建筑物、特别是工厂、居民区保持一定的安全距离，避免各种潜在危险。这是从库址选择的（）来考虑的。

A、地质条件

B、水文条件

C、环境条件

D、水电供应条件

简述一次拉弯的工艺过程。