问题 选择题

正确掌握化学用语和化学基本概念是学好化学的基础。下列有关表述中正确的一组是

A.16O与18O互为同位素;H216O、D216O、H218O、D218O互为同素异形体

B.SiH4、PH3、HCl的稳定性逐渐增强

C.过氧乙酸(CH3COOOH)与羟基乙酸(HOCH2COOH)所含官能团相同;两者互为同分异构体

D.Ca2+的结构示意图为, NH4Cl的电子式为

答案

答案:B

选项A,前半句是对的,但是后半句不对,同素异形体必须是同种原子不同结构,这里四个物质结构相同,原子不同。

选项C,过氧乙酸的结构是,而羟基乙酸的结构是,显然两者的官能团不一样,前者是酸酐,后者是羧酸根和羟基。

选项D,前面钙离子的结构示意图正确,但是后面氯化铵的电子式不正确,正确的写法是

故排除后知B正确,得电子能力即电负性Si<P <Cl,所以键能Si-H<P-H <H-Cl,所以稳定SiH4<PH3 <HCl(共价分子稳定性由键能决定)。通俗的说法就是氧化性越强,氢化物越稳定。

阅读理解

任务型阅读。阅读下面短文,根据所给语境,按要求完成下列各题。

     When we compare ourselves with great people, we may feel very ordinary (平凡的) and unimportant.

However, we must remember that those great people were extraordinary (卓越的). The world has more

than 6 billion people, so it is difficult for all of us to be extraordinary. What can we do? We can try to be

the best people that we can possibly be.

     ①I think this means that we need to be honest and hard-working. We also need to be open-minded and

kind to other people. Most importantly, we need to be ambitious (有雄心的). We need to always set goals

for ourselves and work hard to achieve these goals.

     Madam Curie and Thomas Edison were hard-working, kind and ambitious, and they worked hard to

achieve their goals. Curie gave her life to"ease(减轻) human suffering". Edison spent his life as an inventor.

He invented a camera that showed movement. Later people used cameras to make modem films.

     A famous writer from Ireland once wrote,"We are all in the gutter (社会底层) but some of us are looking

at the stars." ②I often come up with this when I am unable to achieve something. It reminds me that we

are all at a lower level and that we all have a higher goal to work towards. It makes me try to be the best

person that I can possibly be.

1. Is it difficult for all of us to be extraordinary according to the passage?

    ________________________________________________________________

2. What did people use cameras to do later?

    ________________________________________________________________

3. 翻译文章中①处。

    ________________________________________________________________

4. 翻译文章中②处。

    ________________________________________________________________

5. What is the best tide of this passage? (within ten English words) 

    ________________________________________________________________

单项选择题