问题 填空题

下图是工业上生产碳酸锂的部分工艺流程,请根据流程图及已知信息回答问题。

③几种物质不同温度下的溶解度。

(1)从滤渣1中分离出Al2O3的部分流程如下图所示,括号表示加入的试剂,方框表示所得到的物质。写出图中①、②、③表示的各物质,步骤II中反应的离子方程式是       

(2)已知滤渣2的主要成分有Mg(OH)2和CaCO3,写出生成滤渣2反应的离子方程式:

                      

(3)向滤液2中加入饱和Na2CO,溶液,过滤后,用“热水洗涤”的原因是        

(4)工业上,将Li2CO3粗品制备成高纯Li2CO3的部分工艺如下。

①将粗产品Li2CO3溶于盐酸作用解槽的阳极液,LiOH溶液作阴极液,两者用离子选择半透膜隔开,用惰性电极电解。阳极的电极反应式是          

②电解后向产品LiOH溶液中加入过量NH4HCO,溶液生成Li2CO3反应的化学方程式是    

答案

(1)①铝盐(或Al3+)②氨水(或适量氢氧化钠溶液)

Al3++3NH3·H2O=Al(OH)3↓+3NH4+或Al3++3OH-=Al(OH)3

(2)Mg2++2OH-=Mg(OH)2↓    Ca2++CO32-=CaCO3

(3)Li2CO3溶解度随温度升高而减小,热水洗涤可减少Li2CO3的损失。

(4)①2Cl--2e-=Cl2

②2LiOH+NH4HCO3=Li2CO3+(NH4)2CO3+2H2O

题目分析:(1)根据过称图,③灼烧得到Al2O3,②应为Al(OH)3,则①溶液中应该含有Al3+。一般制备Al(OH)3是用可溶性铝盐与氨水反应。所以,离子方程式为Al3++3NH3·H2O=Al(OH)3↓+3NH4+

(2)生成滤渣2,是由于加入了石灰乳和Na2CO3,故离子方程式为Mg2++2OH-=Mg(OH)2↓    Ca2++CO32-=CaCO3

(3)由题中表格可知,Li2CO3溶解度随温度升高而减小,热水洗涤可减少Li2CO3的损失。

(4)①根据题叙述“将粗产品Li2CO3溶于盐酸作用解槽的阳极液,LiOH溶液作阴极液,两者用离子选择半透膜隔开,用惰性电极电解”,阳极发生氧化反应,2Cl--2e-=Cl2

②根据题意可知反应方程式2LiOH+NH4HCO3=Li2CO3+(NH4)2CO3+2H2O

阅读理解

阅读理解。

     Some people think that they have an answer to the problems of automobile crowding and pollution in large

cities. Their answer is the bicycle, or bike.

     In a great many cities, hundreds of people ride bicycles to work every day. In New York City, some bike

riders have even formed a group called "Bike for a Better City". They claim that if more people rode bicycles

to work there would be fewer automobiles in the downtown section of the city and therefore less dirty air

from car engines.

     For several years this group has been trying to get the city government to help bicycle riders. For example,

they want the city to paint special lanes-for bicycles only-on some of the main streets, because when bicycle

riders must use the same lanes as cars, there may be accidents. "Bike for Better City" feels that if there were

special lanes, more people would use bikes.

     But no bicycle lanes have been painted yet. Not everyone thinks it is a good idea. Taxi drivers don't like the

idea-they say it will slow traffic. Some store owners on the main streets don't like the idea-they say that if there

is less traffic, they will have less business. And most people live too far from downtown to travel by bike.

     The city government has not yet decided what to do. It wants to keep everyone happy. On weekends,

Central Park-the largest open place in New York-is closed to cars, and the roads may be used by bicycles only.

But "Bike for a Better City" says that this is not enough and keeps fighting to get bicycle lanes downtown. Until

that happens, the safest place to bicycles may be in the park.

1. The underlined word"automobiles" in the second paragraph means _____.

A. trains

B. cars

C. planes

D. ships

2. Which of the following is TRUE according to the passage?

A. Special lanes are needed on every street.

B. The Central Park is closed to cars on weekdays.

C. "Bike for a Better City" members ride bicycles to work.

D. Accidents won't happen if cars and bikes are on different lanes. 

3. No bicycle lanes have been painted yet because _____.

A. the idea hasn't been accepted by all

B. the main streets are not wide enough

C. the city government can't help to paint the lanes

D. there's no need for most people to travel by bike

4. This passage is mainly about _____.

A. city problems and "Bike for a Better City"

B. "Bike for a Better City" and the city government

C. the government's idea on traffic and city pollution

D. a suggestion on the city problems of traffic and pollution

单项选择题