问题 选择题

已知反应CuCl2+2NaOH=Cu(OH)2↓+2NaCl.向一定量盐酸和氯化铜溶液的混合物中逐滴加入氢氧化钠溶液,产生沉淀的质量与加入氢氧化钠溶液的质量关系如图所示.下列说法正确的是(  )

A.P点表示的溶液pH=7

B.M点表示的溶液中只含有一种溶质

C.从M点到N点溶液质量增加20g

D.P点表示的溶液比N点表示的溶液中氯化钠的质量分数小

答案

A、P点表示氯化铜和氢氧化钠完全反应后,氢氧化钠有剩余,溶液pH>7,故A错误;

B、M点表示氢氧化钠与盐酸恰好反应完,但氯化铜还没有反应,此时溶质是氯化铜、氯化钠,故B错误;

C、从M点到N点是增加了20g,但由方程式CuCl2+2NaOH=Cu(OH)2↓+2NaCl知,溶液应增加少于20g,故C错误;

D、N点表示的氯化铜和氢氧化钠恰好完全反应,P点表示氯化铜和氢氧化钠恰好完全反应后,又增加了一定量的氢氧化钠,两部分中氯化钠的量是一定的,所以P点表示的溶液比N点表示的溶液中氯化钠的质量分数小,故D正确;

故选D.

阅读理解

We go to school every day to become a better

person. So how can we become powerful and start

changes in our own life? Perhaps we can get tips from the US

First Lady Michelle Obama. During her 'visit to China, from March 20-26, Mrs. Obama shared her views on education and youth empowerment with students.

The first lady encouraged Chinese students to aim high and get a good education* In Chengdu No. 7 High School, she told students that having humble (贫寒的) roots doesn't matter as long as you have perseverance(毅力)

Mrs. Obama said her family was not rich. Like many Chinese students, her parents had big dreams for her. She felt the weight of her parents' sacrifices(牺牲) on her shoulders and worked hard to make them proud. Persevering was not easy, though. Sometimes she had to wake up at 4:30 am and study late into the night. "But whenever I got tired or discouraged(气馁 WJ)... I would remember something my mother. always told me. She said: 'A good education is something that no one cart take away from you.''

Mrs. Obama also encourages Chinese students to study abroad to broaden their horizons(开阔眼界) in her speech at Peking University. "As the Chinese saying goes: It is better to travel 10,000 miles than to read 10,000 books," she said. It's not enough to get good grades in school. It's also important to have real experience with languages, cultures and societies different from your own, she noted.

Studying overseas could also benefit future international relations. It could help young people from different countries work together to deal with shared problems such as climate change, Mrs. Obama said.

小题1:From the first paragraph , what kind of views did Mrs. Obama share with the students ?

A.education and development

B.empowerment and perseverance

C.education and youth empowerment

D.education and youth perseverance小题2:From the last paragraph, what is the meaning of the word "benefit"?

A.be good at

B.be good with

C.be bad for

D.be good for小题3:From the passage ,we can learn that

A.Michelle Obama lived a rich life when she was young .

B.Michelle Obama worked hard to make her parents proud..

C.Michelle Obama sometimes had to wake up at 4:30 pm and study late into the night.

D.Michelle Obama would remember something her teachers always told her whenever she got tired or discouraged.小题4:Which of the following is NOT true according to the passage?

A.The first lady encourages Chinese students to aim high and get a good education.

B.The first lady thinks it terrible for students to have humble roots .

C.The first lady thinks that a good education is something that no one can take away from you.

D.Mrs. Obama encouraged Chinese students to study abroad to broaden their horizons.小题5:Which of the following is TRUE according to the passage?

A.We can get tips from the US First Lady Michelle Obama during her visit to Beijing No. 7 High School

B.It's wonderful enough for students to get good grades only in school.

C.It's not important to have real experience with languages, cultures and societies different from your own.

D.Studying overseas could help young people from different countries work together to deal with shared problems.

问答题