下列与处理方法对应的离子方程式不正确的是() A.醋酸洗涤铜器表面的碱式碳酸铜:

来源:www.tikuol.com 发布时间:2017-04-26 10:03
题型:选择题

问题:

下列与处理方法对应的离子方程式不正确的是        (   )

A.醋酸洗涤铜器表面的碱式碳酸铜:Cu2(OH)2CO3 +4H+= 2Cu2++CO2↑+3H2O

B.稀硝酸除银镜:3Ag+4H++ NO3=3Ag++NO↑+2H2O

C.用小苏打治疗胃酸(含盐酸)过多:HCO3+H+= CO2↑+H2O

D.亚硫酸钠除去废水中残留的游离态氯元素:SO32—+C12+H2O=2C1+SO42—+2H+

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题型:填空题
请你给x选择一个合适的值,使方程
2
x-1
=
1
x-2
成立,你选择的x=______.
题型:选择题

-Did you go to school on foot when you were a boy?      

-____.    [ ]

A. Yes,I did              

B. Yes,I am    

C. Yes,I didn't            

D. Yes,I do

题型:阅读理解

第二部分:阅读理解(共两节,满分30分)

第一节(共10小题,每小题2分,满分20分)

阅读下列短文,从每题所给的四个选项(A、B、C和D)中选出最佳选项,并在答题卡上将该项涂黑。

Americans spend their free time in various ways.

America is a country of sports — of hunting, fishing and swimming, and of team sports like baseball and football.Millions of Americans watch their favorite sports on television.They also like to play in community orchestras (管弦乐队), make their own films or recordings, go camping, visit museums,attend lectures, travel, garden, read, and join in hundreds of other activities.The people also enjoy building things for their homes, sewing their own clothes, even making their own photographs.They do these things for fun as well as for economy.

But as much as Americans enjoy their free time, the country is at the same time a “self-improvement” country.More than 25 million adults continue their education, chiefly by going to school in the evening, during their own free time, at their own expense.Added to the time spent on personal activities, Americans a1so devote a great amount of their time to the varied needs of their communities.Many hospitals, schools, libraries, museums, parks, community centers, and organizations that assist the poor depend on the many hours citizens devote to these activities, often without any pay.Why do they do it?

There are several answers.The idea of cooperating and sharing responsibility with one another for the benefit of all is as old as the country itself.

When the country was first founded in 1776, it was necessary for the settlers to work together to live.They had crossed dangerous seas and risked all they had in their struggle for political and religious freedom.There remains among many Americans a distrust of central government.People still prefer to do things themselves within their communities, rather than give the government more control.

Sometimes people offer their time because they wish to accomplish something for which no money is paid, to do something that will be of benefit to the entire community.It is true that some people use their leisure because they are truly interested in the work; or they are learning from the experience.

No matter what the reason is, hundreds of thousands of so-called leisure hours are put into hard, unpaid work on one or another community need.

1.This passage is mainly about ________.

A.why America is a country of sports

B.how Americans spend their free time

C.why America is a “self-improvement” country

D.how Americans are devoted to their community activities

2.The writer mentions the foundation of the country in order to indicate ________.

A.the early history of America

B.the American people’s determination to live

C.the reason for Americans’ willingness to cooperate and share responsibility

D.the American people’ s love for freedom

3.Which of the following best explains the meaning of the underlined word “leisure”?

A.work time           B.energy                C.effort                  D.spare time

4.What can we infer from the text?

A.The first settlers left their hometown for political and religious reasons.

B.Many Americans don’t trust the central government.

C.American people enjoy building things for their homes just for fun.

D.Americans continue their education at their own expense.

题型:单项选择题

已知盐水若干克,第一次加入一定量的水后,盐水浓度为3%;第二次加入同样多的水后,浓度变为2%,那么第三次加入同样多的水后盐水的浓度为()。

A.1.6%

B.1.5%

C.1.2%

D.1%

题型:问答题 简答题

为什么要强化对中华文化的认同?