问题 选择题

用Cl2生产某些含氯有机物时会产生副产物HC1。利用反应A,可实现氯的循环利用。

反应A:4HCl+O2  2Cl2+2H2O

已知:Ⅰ、反应A中,4mol HCI被氧化,放出115.6kJ的热量。

Ⅱ、

判断下列说法正确的是

A.反应A的△H >-115.6 kJ·mol-1

B.H2O中H—O 键比HCl中H—Cl键弱

C.由Ⅱ中的数据判断氯元素的非金属性比氧元素强

D.断开1 mol H—O 键与断开 1 mol H—Cl 键所需能量相差约为32kJ

答案

答案:D

题目分析:反应热就是断键吸收的能量和形成化学键所放出的能量的差值,所以有4x+498kJ-2×243kJ-2×2×y=-115.6kJ,解得y-x=31.9,所以选项D正确,A和B不正确。键能大小不能作为判断氯元素和氧元素非金属性强弱的依据,C不正确,答案选D。

点评:该题是中等难度的试题,试题设计新颖,基础性强。该题的关键是明确从微观的角度去理解反应热的计算,有利于培养学生严谨的逻辑思维能力和发散思维能力,以及灵活运用基础知识解决实际问题的能力。

阅读理解

My father was 44 and knew he wasn’t going to male it to 45. He wrote me a letter and hoped that something in it would help me for  the  rest  of my life.

Since the day 1 was 12 and first read his letter, some of his words have lived in my

beart. One it aways times out. “Right now, you are pretending to be a time-killer. But I know that one hay, you will do something great that will set you among the very best.” Knowing that my dad believed in me gave me permission to believe in myself. “You will do something great.” He didn’t know what that would be, and neither did I, but at times in my life when I’ve felt proud of myself, I remember his words and wish he were here so I could ask. “Is this what you were talking about, Dad? Should I keep going?”

A long way frim 12 now, I realize hew would have been proud when I made any progress. Lately, thongn. I’ve come to believe he’d want me to move on to winat com next: to be nrood of and believe in, somebody else. It’s time to start writing my own letters to my children. Our children look to us with the same unanswered question we had. Our kids don’t  hold back because they’re afraid to fail. They’re only afraid of failing us. They don’t worry about being disappointed. Their fear-as mine was until my father’s letter-is of being a disappointment.

Give your chikdren permission to succeed. They’re witing for you to believe in them. I always knew way parents loved me. But trust my That elic will be more comlece, that love will be more real, and their belief in the nelces whi be greater if you write the words on their hearts; “Don’t worry; you’ll do something great.” Not having that blessing from their parents may be the only thing holding them back.

1.We learn from the text that the author___________.

A.lost his father when he was young

B.worked hard before he read his father’s letter

C.asked his father permission to believe in himself

D.knew execty at thing his father wanted him to do

2.What clis the hor tell us in the 3rd passgiaph?

A.Children need their parents’letters.

B.Children are afraid to be disappointcd.

C.His children’s fear of failure held them back.

D.His father’s letter removed his fear of failing his parents.

3.Which of the following is true of the author?

A.He got no access to success.

B.He wrote back to his father at 12.

C.He was surk his parents loved him.

D.He whce asked his father about the letter.

4.The main purpose of the text is to _______.

A. describe children’s thinking

B.answer some questions children have

C.stress the importance of communication

D.advise parents to encourage their children

单项选择题 配伍题