下列离子方程式表达正确的是 A.向硫酸铵溶液中滴加氢氧化钡溶液:Ba2++SO4

题型:选择题

问题:

下列离子方程式表达正确的是

A.向硫酸铵溶液中滴加氢氧化钡溶液:Ba2+SO42=BaSO4

B.铜片跟浓硝酸反应:3Cu+2NO3+8H=3Cu2+2NO↑+4H2O

C.苯酚钠溶液中通入少量CO2:2C6H5O+CO2+H2O2C6H5OH+CO32

D.硝酸亚铁溶液和稀盐酸混合:3Fe2+4H+NO3=3Fe3+NO↑+2H2O

考点:离子方程式
题型:选择题
曲线y=
1
2
x2-2
在点(1,-
3
2
)处切线的倾斜角为(  )
A.1B.
π
4
C.
4
D.-
π
4
题型:选择题

发明专利权,实用新型和外观设计专利权的期限不同,其正确的选项是( )。

A.前者为20年,后者为10年

B.前者为10年,后者为20年

C.前者后者均为10年

D.前者后者均为20年

题型:选择题

(2011年山东滨州,24题)小林、小军和小明在实验室用右图装置做CaCO3受热分解的实验,加热一段时问后,他们对试管内固体的成分进行探究。

【提出问题】加热CaCO3后试管内的固体成分是什么?

【建立假设】小林的假设:CaCO3未分解,固体成分为CaCO3

小军的假设:CaCO3完全分解,固体成分为          

小明的假设:CaCO3部分分解,固体成分为          

【收集证据】(1)小军取少量固体于试管中,加适量水振荡后静置,再滴

几滴无色酚酞试液,溶液变红。可知小军加水时发生反应的

化学方程 式为————————。

(2)小明向小军实验后的试管中滴加过量稀盐酸,发现有气泡生成。

【获得结论】通过实验可知        的假设是成立的。

【交流与评价】实验结束后,在组内交流讨论过程中部分同学提出:在实验中若增加下列仪器中的         (填编号)就可以直接根据实验现象判断CaCO3是否分解。

题型:选择题

下列关于青春期心理卫生的叙述,不正确的是[ ]

A.正确对待身体变化,性器官的发育,第二性征的出现等

B.将自己性知识中的疑惑埋藏在心里

C.树立远大理想情操,把精力集中在学习和培养高尚情操上

D.正常开展人际交往

题型:选择题

My oldest child, Emma, just returned to campus after a long holiday break to finish up her last period of college. These days, friends and family have begun flooding me with one question: What is she going to do after graduation?

The job market is, after all, awfully tough. Just this month the Federal Reserve Bank published a study showing that “recent graduates are increasingly working in low-paid jobs or working part-time.” The bright spot, according to the study, is for students who majored(主修) in STEM— science, technology, engineering and mathematics — areas in which recent graduates “have tended to do relatively well”.

But Emma is a student of the humanities(人文) at a small college. She’s an American Studies major with a focus on the politics and culture of food. For quite a while, I think her field of study is so fashionable right now that I’m not the least bit worried she will find a good job. Yet the more I’ve thought about it, the more I’ve decided to be honest. “I’m not sure what Emma is going to do,” I now say. “But she’s gotten a great education and has really found her interest. — and I know those things will serve her well over the course of her life.”

Nowadays, more and more universities and colleges are being measured by the salaries of their recent graduates. In this climate, encouraging your kid to study the humanities, seems, at best, unwise or, at worst, unconcerned with earning a living. But a college is not a vocational(职业) school. And promoting STEM subjects should not be society’s only answer to helping the next generation grow in a competitive world.

From the beginning, we never urged Emma to pick a college or a major with an eye on its expected return on money, as more and more families are doing. To Emma, what really matters will be something that we may not be able to measure for quite a long time: Emma’s contribution to the world and how happy she is in it.

小题1:The author’s friends and family_________.

A.are worried about Emma’s safety

B.have been worrying about the flood

C.are concerned about Emma’s future

D.are worried about the job market小题2:What can we learn from Paragraph 2?

A.The number of the graduates is increasing.

B.STEM graduates can be better employees.

C.STEM graduates are in relatively greater demand.

D.More and more graduates like to do a part-time job.小题3:Why did Emma choose a major in the humanities?

A.Because she is interested in it.

B.Because her mother told her to.

C.Because it is increasingly popular.

D.Because she wants further education.小题4:According to the author, what matters most in choosing a major is that_________.

A.it should be among the STEM

B.it should be fashionable and interesting

C.it should allow a good job and a high salary

D.it should bring achievements and happiness

更多题库