问题 选择题

下列说法正确的是

A.在2H2O2=2H2O +O2反应中,每生成32g氧气,则转移4NA个电子

B.612C、613C为不同的核素,化学性质有较大的差异

C.新制氯水显酸性,向其中滴加少量紫色石蕊试液,充分振荡后溶液呈红色

D.将SO2通入品红溶液,溶液褪色后加热恢复原色;将氨气通入酚酞溶液中,变色后加热也能恢复原色

答案

答案:D

题目分析:A、在2H2O2=2H2O +O2反应中,双氧水中氧元素的化合价从-1价升高到0价,所以每生成32g氧气(即1mol氧气),转移2NA个电子,A不正确;B、612C、613C为不同的核素,但质子数相同,二者互为同位素,化学性质几乎相同,B不正确;C、氯气溶于水生成盐酸和次氯酸,因此新制氯水显酸性,同时还具有强氧化性,具有漂白性,所以向其中滴加少量紫色石蕊试液,充分振荡后溶液先呈红色后褪色,C不正确;D、SO2具有漂白性,但不稳定,加热后又恢复到原来的颜色,因此将SO2通入品红溶液,溶液褪色后加热恢复原色;氨气溶于水生成氨水,溶液显碱性,但氨水不稳定,加热又分解释放出氨气,因此将氨气通入酚酞溶液中,变色后加热也能恢复原色,D正确,答案选D。2和氨水的性质

阅读理解

阅读理解。

      "When can I get a cell phone?" The answer is when your parents think you need one, though many kids

seem to be getting them around age 12 or 13. Some younger kids may have them because their parents see

it as a matter of safety and convenience. For example, a kid can call mom and dad when sports practice is

over. And a cell phone can give kids almost instant access (快捷通道) to their parents if something goes

wrong or they need help. It can give parents quick access to their kids so they can check on them and

make sure they're OK.

      If you do get a cell phone, make some rules with your parents, such as how many minutes you're

allowed to spend on the phone, when you can use your phone, when the phone must be turned off, and

what you will do if someone calls you too often, and so on.

     You'll also have to learn to take care of the phone in your life. Keep it charged (充电) and store it in the

safe place so it doesn't get lost. And whatever you do, don't use it in the bathroom. I know someone who

dropped her phone in the toilet!

1. Parents buy cell phones for their kids because _____. [ ]

A. they think it is necessary

B. they think their kids are old enough

C. they have asked the author for advice

D. they want to follow their kids wherever they are

2. The author of the passage _____. [ ]

A. wants to describe how children use cell phones

B. knows nothing about when children can have a cell phone

C. may have done a survey on kids using cell phones

D. has been a teacher for many years

3. Which of the following is true?[ ]

A. It is too young for kids of 12 or 13 to get a cell phone.

B. A cell phone is useful for kids and their parents.

C. The author is against the idea of kids to have cell phones.

D. Mos t kids are considering having cell phones.

4. Who is the passage most probably written by? [ ]

A. Parents who have bought phones for their kids.

B. Someone who does cell phone business.

C. A teacher who cares most about school safety.

D. Someone who works for children's education.

5. Which might not be a rule for kids with a cell phone?  [ ]

A. Keep it on all the time.

B. Make a call if something goes wrong.

C. Don't use it in the bathroom.

D. Take care not to lose it.

选择题