4、(2009·平原县)下列是小明课堂笔记中记录的有关化学用语，其中准确无误的是(　　 )

A．氦的元素符号：Ha　　　　　　　　 B．2个碳酸根离子：2CO₃

C．氧化铝的化学式：Al₂O₃　　　　　　 D．镁在空气中燃烧：Mg+O₂MgO₂

3、(2009年烟台)下图是工业上制备氢气的微观示意图，其中不同的“球”代表不同的原子。下列说法不正确的是(　 　)

A．图中能表示氢分子的是“”

B．反应前后，原子的种类、数目不变

C．该反应中共涉及两种单质和三种化合物

D．该反应中参加反应的两种分子的个数比为1 :1

2、(2009·德州)为预防手足口病，可用84消毒液(主要成分是NaClO)对生活用品消毒，用酒精是不管用的。有关NaClO的说法错误的是(　 ))

A、NaClO中氯元素的化合价为－1价　　 B、NaClO是一种化合物

C、NaClO由三种元素组成　 　 　　　　　D、NaClO中Na、Cl、O的原子个数比为1:1:1

1、(2009·黔东南州)下列叙述完全符合质量守恒定律的是(　 )

A．水结成冰前后，质量保持不变

B．50mL水和50 mL乙醇混合后总体积小于100 mL

C．在100g过氧化氢溶液中，含有30g过氧化氢和70g水

D．1.2g碳与3.2g氧气恰好完全反应可生成4.4g二氧化碳学

第三节：书面表达(满分15分)

假如你是Mike，是美国Jenks High School与成都七中交换项目的学生，请就本校食堂服务(canteen service)的状况给校长写一封信。内容包括：

字数：100左右。

Dear Mr. Principal,

I am an exchange student from Jenks High School. And I have been here in Chengdu No 7 High School for some time. I’d like to say something about the canteen service in our school.

He said he wouldn’t go back to be rich for anything. ________

Tom had to drop out school because of his poor family. _____

I spend all of my money very fast and save nothing of it. _____

Over time, a lot of soil has removed, causing serious erosion. ______

People were asked to comment scenes from this film. ______

It is you who has the most important role to play in stopping the erosion. ______

It is amazing that all this started from 5 Yuan. ______

8．A person like him is difficult to get along. ______

We should do all what we could to stop this airport. ______

I found some of what he said very worried. ______

The thief was lucky enough to escape from being caught. _____

10. I’ve got about $10 in my w_______________. (钱包)

9. B___________(举止) yourself, or you’ll not be allowed to take part in the party.

When the police caught the thief, he _________(假装) an ordinary man.

He failed in his first a__________(　 尝试 )to ride a horse, but he would try a second time.

This company shows great _________( 尊重 )for human rights.

We should honor those who have made great ___________(贡献) to the society.

They ___________(宣布) the date of their wedding in the paper.

He was not a regular ___________(顾客) of that shop, for he just dropped in sometimes.

He is a j___________(新闻记者) collecting and writing news reports for newspapers and magazines.

8. A good salesman must be __________(进取的) if he wants to succeed.

38．(8分)[物理-物理3-5]

(1)大量氢原子处于不同能量激发态，发生跃迁时放出三种不同能量的光子，其能量值分别是：1．89eV,10．2eV,12．09eV。跃迁发生前这些原子分布在_______个激发态能级上，其中最高能级的能量值是______eV(基态能量为-13．6eV)。

(2)如图所示，滑块A、C质量均为m，滑块B质量为m。开始时A、B分别以的速度沿光滑水平轨道向固定在右侧的挡板运动，现将C无初速地放在A上，并与A粘合不再分开，此时A与B相距较近，B与挡板相距足够远。若B与挡板碰撞将以原速率反弹，A与B碰撞将粘合在一起。为使B能与挡板碰撞两次，应满足什么关系？