问题 填空题

多晶硅被称为“微电子大厦的基石”,制备中副产物以SiCl4为主,它对环境污染很大,能遇水强烈水解,放出大量的热。研究人员利用SiCl4水解生成的盐酸和钡矿粉(主要成份为BaCO3,且含有铁、镁等离子)制备BaCl2·2H2O,工艺流程如下:

已知:常温下Fe3+、Mg2+完全沉淀的pH分别是:3.4、12.4。

(1)SiCl4水解反应的化学方程式为_________________________________________________。过滤操作需要的玻璃仪器有_________________________________。

(2)加钡矿粉调节pH=7的作用是________________________、_______________________。

(3)加20% NaOH调节pH=12.5,得到滤渣A的主要成分是_______________________。

(4)BaCl2滤液经__________、_________、过滤、洗涤,再经真空干燥后得到BaCl2·2H2O。

(5)10吨含78.8 % BaCO3的钡矿粉理论上最多能生成BaCl2·2H2O_________吨。实际产量为9.70吨,相对误差为__________________%。

答案

(1)SiCl4+4H2O→H4SiO4↓+4HCl(2分);烧杯、漏斗、玻璃棒(2分)

(2)使BaCO3转化为BaCl2,使Fe3+完全沉淀(2分)     

(3)Mg(OH)2(2分)

(4)蒸发浓缩、冷却结晶(2分) 

(5)9.76;-0.61 (2分)

题目分析:(1)根据水解机理相当于水中的羟基取代了氯原子,即SiCl4水解反应的化学方程式为SiCl4+4H2O→H4SiO4↓+4HCl。过滤操作需要的玻璃仪器有烧杯、漏斗、玻璃棒。

(2)加钡矿粉调节pH=7的作用是使BaCO3转化为BaCl2,使Fe3+完全沉淀。

(3)根据题中信息,常温下Fe3+、Mg2+完全沉淀的pH分别是:3.4、12.4。加20% NaOH调节pH=12.5,主要是沉淀镁离子,得到滤渣A的主要成分是Mg(OH)2

(4)BaCl2滤液经蒸发浓缩、冷却结晶,过滤、洗涤,再经真空干燥后得到BaCl2·2H2O。

(5)反应关系式为

BaCO3~BaCl2·2H2O

197         244

10×78.8%     m

m==9.76吨

相对误差=(9.7-9.76)/9.7=-0.61%

阅读理解

In the eighteenth century one of the first modern economists, Adam Smith, thought that “ the whole annual produce of the land and labour of every country” provided revenue to “three different orders of people: those who live by rent, those who live by wages, and those who live by profit”. Each successive stage of the industrial revolution, however, made the social structure more complicated.

Many intermediate groups grew up during the nineteenth century between the upper middle class and the working class. There were small-scale industrialists as well as large ones, small shopkeepers and tradesmen, officials and salaried employees, skilled and unskilled workers, and professional men such as doctors and teachers. Farmers and peasants continued in all countries as independent groups.

During the nineteenth and early twentieth centuries the possession of wealth inevitably affected a person’s social position. Intelligent industrialists with initiative made fortunes by their wits which lifted them into an economic group far higher than that of their working-class parents. But they lacked social training of the upper class, who despised them as the “new rich.”

They often sent their sons and daughters to special schools to acquire social training. Here their children, mixed with the children of the upper classes, were accepted by them, and very often found marriage partners from among them. In the same way, a thrifty, hardworking labourer, though not clever himself, might save for his son enough to pay for an extended secondary school education in the hope that he would move in a “white-collar” occupation, carrying with it a higher salary and a move up in the social scale.

In the twentieth century the increased taxation of higher incomes, the growth of the social services, and the wider development of educational opportunity have considerably altered the social outlook. The upper classes no longer are the sole, or even the main possessors of wealth, power and education, though inherited social position still carries considerable prestige.

小题1:What criterion did Adam Smith seem to go by in his classification of social groups?

A.The amount of wealth

B.The amount of money

C.The social status

D.The way of getting money小题2:If you compare the first and second paragraph, what groups of people did Adam Smith leave out in his classification?

A.Officials and employees.

B.Peasants and farmers.

C.Doctors and teachers.

D.Tradesmen and landlords.小题3:Who were the ‘new rich’ during the nineteenth and early twentieth centuries?

A.They were still the upper class people.

B.They were owners of large factories.

C.They were intelligent industrialists.

D.They were skilled workers who made their fortune.小题4:According to the passage, what did those people do who intended to make their children move up in the social ladder?

A.They saved a lot of money for their children to receive higher education.

B.They tried to find marriage partners from the children of the upper class.

C.They made greater fortunes by their wits.

D.They worked even harder to acquire social training.小题5: In the twentieth century class differences have been partly smoothed out by ____.

A.increased income and decreased taxation

B.taxation, social services and educational opportunities

C.education, the increase of income and industrial development

D.the decrease of the upper class population

单项选择题 共用题干题