问题 选择题

在水蒸发的过程中,下列说法正确的是

A.水分子变小

B.水分子间的间隔不变

C.水分子分解成氢原子和氧原子

D.水分子不断运动

答案

答案:D

考点:

专题:物质的微观构成与物质的宏观组成.

分析:从分子的基本性质入手,分子是构成物质的一种粒子,它的体积很小,分子在不断运动,分子间有一定的间隔.汽油挥发由液态变成了气态是分子在不断运动,分子之间的间隔增大的结果.

解答:解:A、水蒸发由液态变成了气态,分子的间隔变大,分子的大小不变;故错

B、水分子之间间隔不变,水蒸发后体积变大,水分子本身没有改变,改变的是分子间的间隔,变大了,故错;

C、氢、氧原子不发生改变,水蒸发是物理变化,水分子不变,其中的氢原子和氧原子也不变,故错;

D、水分子不断运动,该观点符合分子是不断运动的特点,故对;

故选D

点评:水蒸发是物理变化,物理变化改变的是粒子间的间隔或排列;在化学变化中,分子才能分解成原子,原子重新组合成新的分子.

阅读理解

Two-year-old hero Ye Chengfeng saved most of his family from a deadly gas leak(泄漏). As his grandfather lay dead, the child woke up his grandmother and saved five other family members from death.

More and more British school kids use their mobile phones to cheat(作弊)in exams. They use them to send messages to get the answers. So far this year, 1,013 students were caught cheating with mobile phones. Teachers are now teaching themselves so they can find the cheats. They also ask the students to hand the phones in before exams.

A new study shows that girl chimps(黑猩猩) are faster to use tools than boys! Experts found that girl chimps in East Africa use sticks to dig in the soil two years earlier than boys do. But they don’t know why. Girls watched their moms work, but the boys climbed trees. Yes, human girls always learn to write and draw first, but boys often run and play balls earlier than girls.

In Germany, doctors have three ways to help kids who are addicted (上瘾的)to the Internet. First, learning art — Kids learn painting or singing; Second, doing sports — Kids do swimming or horse riding. The last one is to go into nature — Kids plant flowers and grow vegetables. Doctors want kids to find other ways to have fun rather than surf the Internet.

小题1:How many family members did 2-year-old Ye Chengfeng save?

A.Six.

B.Five.

C.Three.

D.Four.小题2:The British teachers are teaching themselves to________.

A.send messages to each other

B.find their students’ cheats in exams

C.stop the students from using their mobile phones

D.ask the students to hand in their phones before exams小题3:According to the third piece of news, we know ________.

A.chimps are cleverer than monkeys

B.only chimps in East Africa can use tools

C.human boys always learn to write and draw earlier than girls

D.experts don’t know why girl chimps use tools faster than boys小题4:The German doctors help kids addicted to the Internet so that they can________.

A.go into nature

B.enjoy their school life better

C.become famous painters and singers

D.find some other ways to enjoy themselves小题5:Choose the best title for each piece of news above from the following six ones:

①Girls learn faster than boys?   ②Phone cheats      ③Little hero

④No cheating!      ⑤Internet cure      ⑥Go into nature

A.①⑤④⑥

B.③④⑥⑤

C.③②①⑤

D.②③①⑤

单项选择题