5． 在一定条件下A与B反应可生成C和D，其能量变化如图：

下列有关反应A+B₌₌₌C+D的说法正确的是(　 )

　　 A．反应前后原子的种类和数目一定不变

B．反应前后分子的种类和数目一定改变

C．反应物的总能量E₁与生成物的总能量E₂一定相等

D．此反应一定有热量的变化

4．在2A+B 3C+4D反应中，表示该反应速率最快的是

A．υ(A)＝ 0.5 mol/(L·s)　　　　　　　 B．υ(B)＝ 0.3 mol/(L·s)

C．υ(C)＝ 0.8 mol/(L·s)　　　 　　　　D．υ(D)＝ 1 mol/(L·s

3．已知热化学方程式：　 H₂O(g)＝H₂(g) + 1/2O₂(g)　　　 △H = +241.8kJ／mol

　　　　 H₂(g) + 1/2O₂(g) ＝ H₂O(1)　　　 △H = －285.8kJ／mol

　 当1g液态水变为水蒸气时，其热量变化是(　 )

　 A．吸热88kJ　　　 B． 吸热2.44KJ　　 C．放热44kJ　　　 D． 吸热44KJ

A. C₆H₁₂O₆(葡萄糖aq)+6O₂ 6CO₂+6H₂O　

B. CH₃COOH+KOH CH₃COOK+H₂O

C. 反应物的总能量大于生成物的总能量　

D．破坏反应物全部化学键所需能量大于破坏生成物全部化学键所需能量

2．氨水中所含有的分子和离子有(　 )

① 　　　 ②H₂O　　 ③NH₃　　 ④NH₃·H₂O　　　 ⑤H⁺　　 ⑥OH^-

A.①②③　　　 B.②③④⑤　　　 C.②③④⑤⑥　　　 D.①②③④⑤⑥

10.　 I’m often late for school. The teacher is so angry that he threatens that if I’m late again, I will be dismissed.

Step 4　 Writing Your advice is good and helpful. All of you are qualified editors. Now I have just received a letter from a lonely boy. Read the letter, what is his problem? What is your advice for him? Write a reply.

Step 5　 Homework Write a story about you and your friend.

9.　　　 I’d like to be monitor, but at the same time I doubt whether I have such ability.

8.　　　 I quarreled with my best friend 3 days ago. Up to now, we haven’t said a word to each other.

7.　　　 My mother has just given birth to my little brother. I’m worried that the baby will rob me of my parents’ love and even everything.

6.　　　 I don’t like the way Mr. Li teaches us English, so I’m not interested in English any longer.

5.　　　 I want to travel to WuZhen Town with my fiends this weekend, but my parents don’t allow me to go.