问题 填空题

写出下列化学方程式,并回答有关问题.

化学反应化学方程式简答
电解水______与负极相连的玻璃管内产生的气体是

______

高温煅烧石灰石______将煅烧后的固体放入滴有酚酞的试液的水中,现象是

______

无水硫酸铜与水反应______现象是

______

木炭和氧化铜反应______该反应中的氧化剂是

______

镁带在空气中燃烧______该反应中反应物的质量比

______

答案

电解水的化学方程式为:2H2O

 通电 
.
 
2H2↑+O2↑;依据电解水实验中“正氧负氢”判断;与负极相连的玻璃管内产生的气体是H2

高温煅烧石灰石的化学方程式为:CaCO3

 高温 
.
 
CaO+H2O+CO2↑;将煅烧后的固体氧化钙放水中生成氢氧化钙,无酚遇碱红,实验实验现象是变红;

无水硫酸铜与水反应的化学方程式为:CuSO4+5H2O=CuSO4?5H2O;无水硫酸铜遇水变蓝色,因此实验现象是水变蓝;

木炭和氧化铜反应的化学方程式为:C+2CuO

 高温 
.
 
2Cu+CO2↑;在氧化还原反应中氧化剂(反应物)→得电子→化合价降低;依据反应前后化合价判断,该反应中的氧化剂是CuO;

镁带在空气中燃烧的化学方程式为:2Mg+O2

 点燃 
.
 
2MgO;该反应中反应物的质量比为:(24×2):(16×2)=3:2;

故答案为:

化学反应化学方程式简答
2H2O
 通电 
.
 
2H2↑+O2
H2
CaCO3
 高温 
.
 
CaO+H2O+CO2
变红
CuSO4+5H2O=CuSO4?5H2O水变蓝
C+2CuO
 高温 
.
 
2Cu+CO2
CuO
2Mg+O2
 点燃 
.
 
2MgO
3:2

单项选择题
阅读理解

阅读理解。

     Human remains of ancient settlements will be reburied and lost to science under a law that threatens

research into the history of humans in Britain, a group of leading archaeologists (考古学家) says.In a letter addressed to the justice secretary, Ken Clarke, 40 archaeologists write of their “deep and widespread

concern” about the issue.It centres on the law introduced by the Ministry of Justice in 2008 which requires all human remains unearthed in England and Wales to be reburied within two years, regardless of their age.The decision means scientists have too little time to study bones and other human remains of national and

cultural significance.

     "Your current requirement that all archaeologically unearthed human remains should be reburied,

whether after a standard period of two years or further special extension, is contrary to basic principles of archaeological and scientific research and of museum practice."  they write.

     The law applies to any pieces of bone uncovered at around 400 dig sites, including the remains of 60 or so bodies found at Stonehenge in 2008 that date back to 3,000 BC.Archaeologists have been granted a

temporary extension to give them more time, but eventually the bones will have to be returned to the

ground.

     The arrangements may result in the waste of future discoveries at sites such as Happisburgh in Norfolk, where digging is continuing after the discovery of stone tools made by early humans 950,000 years ago.If

human remains were found at Happisburgh, they would be the oldest in northern Europe and the first

indication of what this species was.Under the current practice of the law those remains would have to be

reburied and effectively destroyed.

     Before 2008, guidelines allowed for the proper preservation and study of bones of sufficient age and

historical interest, while the Burial Act 1857 applied to more recent remains.The Ministry of Justice

assured archaeologist two years ago that the law was temporary, but has so far failed to revise it.

     Mike Parker Pearson, an archaeologist at Sheffield University, said: "Archaeologists have been

extremely patient because we were led to believe the ministry was sorting out this problem, but we feel that we cannot wait any longer."

     The ministry has no guidelines on where or how remains should be reburied, or on what records should be kept.

1.According to the passage, scientists are unhappy with the law mainly because _____.

A.it is only a temporary measure on the human remains

B.it is unreasonable and thus destructive to scientific research

C.it was introduced by the government without their knowledge

D.it is vague about where and how to rebury human remains

2.Which of the following statements is true according to the passage?

A.Temporary extension of two years will guarantee scientists enough time.

B.Human remains of the oldest species were dug out at Happisburgh.

C.Human remains will have to be reburied despite the extension of time.

D.Scientists have been warned that the law can hardly be changed.

3.What can be inferred about the British law governing human remains?

A.The Ministry of Justice did not intend it to protect human remains.

B.The Burial Act 1857 only applied to remains uncovered before 1857.

C.The law on human remains hasn't changed in recent decades.

D.The Ministry of Justice has not done enough about the law.

4.Which of the following might be the best title of the passage?

A.New discoveries should be reburied, the government demands

B.Research time should be extended, scientists require

C.Law on human remains needs thorough discussion, authorities say

D.Law could bury ancient secrets for ever, archaeologists warn