问题 实验题

(1)测定空气中氧气的体积分数可以采用下图甲乙两种装置,甲装置实验过程中,红磷燃烧产生大量白烟,当温度降到室温,打开止水夹,会观察到____________现象。乙装置可视为甲的改进装置,乙装置与甲装置相比较,优点在于____________(任答一点)。

        

     A                   B                                                                        

          甲                                                 乙                       

(2)乙装置实验完后,变黑的铜丝可用稀硫酸处理得到硫酸铜。工业上制备硫酸铜通常有两种方案。

方案一:

方案二:

其中方案_______更适合工业生产,主要原因是____________________________(任答一点)。

(3)方案二产生的SO2具有和CO2类似的性质,都能使澄清石灰石变浑浊,除此之外,SO2还能被酸性高锰酸钾溶液吸收,使高锰酸钾溶液颜色由紫色变为无色。某化学兴趣小组为研究煤燃烧的气体产物,将煤燃烧产生的气体通入澄清石灰石,观察到石灰水变浑浊。根据现象,猜想一:煤燃烧产生的气体是CO2;猜想二:煤燃烧产生的气体是SO2;猜想三:煤燃烧产生的气体是____________________。为了验证此气体成分,该小组设计了如下图实验,其中B装置的作用是________________;当观察到____________________现象,证明猜想三成立。

                            酸性高锰   酸性高锰  澄清         

                                 酸钾溶液   酸钾溶液  石灰水          

                        A             B            C

答案

(1)水进入到A瓶 ,约占A瓶容积的1/5   ;测量更为精确或减少污染

(2)一  ;无污染大气的SO2产生或H2SO4利用率更高  

(3)SO2和CO2的混合气体  ;检验SO2是否被除尽  ;A瓶溶液褪色,B瓶溶液不褪色,C瓶溶液出现白色沉淀或变浑浊

阅读理解

阅读理解。

     Last year more than one million Filipinos worked abroad as servants, nurses, sailors and in other difficult

but low-paid jobs. Southeast Asians leave their poorer countries for their richer neighbours.

     Many of these wage-earners return in the end. In the meantime, they send home huge amounts of money-

in the Philippines' case, over 10% of its GDP. Between January and November, the amount was up 18% on

the same period of 2005, Poverty and unemployment are still high in the Philippines and other labour-exporting

(劳务输出) countries. They would be far worse but for this outflow of bodies and inflow of dollars. As for

those Asian countries that import (输入) labour, as in Europe, falling birth rates mean they are going to need

more foreign workers.

     On January 13th leaders of the Association of Southeast Asian Nations (ASEAN) signed an agreement to

help migrant (流动的) workers-with the realization that the flow of labour between their countries is a growing

problem that they cannot blame on outsiders. A 2005 study showed that 8.4 million Southeast Asians worked

outside their home countries, but this did not include the huge numbers of Indonesians doing so without papers.

So the true total is probably rather higher.

     Of the ten ASEAN countries, the Philippines, Indonesia, Myanmar, Cambodia, Vietnam and Laos export

labour, Singapore and Brunei import it, and Thailand and Malaysia do both. Sziraczki of the UN's International

Labour Organization points out that, in the next ten years, the total labour force of the worker exporting

countries should grow by about a third. It makes sense to work on the problem before it gets out of control.

     People in the receiving countries seem to be worried about competition for their jobs. Most Thais said their

government should admit (准入) no more foreign workers, and a few thought otherwise. Even in Singapore,

just over ball of people are against admitting more foreign workers. Malaysians think that the increase in foreign

workers has worsened crime rates (犯罪率).

1. It can be inferred from the case of the Philippines that _____. 

A. the country is Asia's main source of migrant workers

B. labour exports lead to a 10% growth of its GDP

C. the outflow of labour helps solve its social problems

D. the country both exports and imports labour force

2. The flow of labour is a growing problem because _____.

A. there is a greater flow of labour than reported

B. more Indonesians work abroad without papers

C. some countries suffer from low birth rates

D. the ASEAN is against admitting foreign workers

3. For the labour-importing countries, the flow of labour may lead to _____.

A. higher birth rates

B. lower crime rates

C. greater money inflows

D. stronger job competition

4. The writer of the text seems to _____.

A. support the flow of labour between countries

B. report fairly on the question of labour flow

C. express his worries over the ASEAN's decision

D. regard the outflow of labour as a serious problem

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