问题 填空题

水处理技术在生产、生活中应用广泛。

(1)含有较多_______离子的水称为硬水。硬水加热后产生碳酸盐沉淀的离子方程式为__________(写出一个即可)

(2)将RH型阳离子交换树脂和ROH型阴离子交换树脂串接来软化天然硬水,应先使硬水通过________(填“RH”或“ROH”)型离子交换树脂,原因是_____________________________________。

(3)通过施加一定压力使水分子通过半透膜而将大分子或离子截留,从而获得纯净水的方法称为_______________________。电渗析法净化水时,使离子通过半透膜的推动力是_____________________________。

(4)检验蒸馏水的纯度时,最简单易行的方法是测定水的_____________________________。

答案

(1)Ca2+、Mg2+;Ca2++2HCO3-CaCO3↓+CO2↑+H2O(或Mg2++2HCO3-MgCO3↓+CO2↑+H2O)

(2)RH;先通过阴离子交换树脂可能产生Mg(OH)2等沉淀而影响树脂交换效果

(3)反渗透法;电势差(或电场力)

(4)电导率(或电阻率)

填空题
完形填空
完型填空。
     We all know that it is __1__to keep healthy. But not all people know ___2__to
keep healthy. After five days' hard work, we need to have a good rest at weekends.
But it seems that some don't know how to spend weekends in the right way. They
enjoy ___3__ cards at night and don't go to bed until midnight or even later. Some
gamble (赌博) all night. They forget that to get___4__sleep is essential (必要的) for health. Some never get up early in the __5___ and take some exercise. It is true that
doing exercise is very important for us to keep ___6__. Some smoke a lot. They f
orget that __7___ smokers are more likely (可能) to have lung cancer (肺癌) than
those who don't smoke. Some drink too much wine. ____8___ too much is harmful (有害) to the body. Some eat too much rich food and get fatter and fatter. If you are much too fat, you may always ____9___ tired. Vegetables are good to the body. But some don't like eating vegetables. _____10___ is also very good to body. As a
saying (谚语) goes, "An apple every day keeps the doctor away." So don't forget to
eat some fruit.
( ) 1. A. important
( ) 2. A. when    
( ) 3. A. to play  
( ) 4. A. much    
( ) 5. A. morning  
( ) 6. A. health  
( ) 7. A. light    
( ) 8. A. Drink    
( ) 9. A. are      
( ) 10.A. Water    
B. good      
B. how      
B. play      
B. many      
B. afternoon
B. healthy  
B. heavy    
B. Drinking  
B. keep      
B. Milk      
C. nice    
C. what    
C. playing  
C. a little
C. evening  
C. clear    
C. good    
C. Eat      
C. say      
C. Tea      
D. happy  
D. why    
D. plays  
D. enough  
D. day    
D. up      
D. strong  
D. Smoke  
D. feel    
D. Fruit