问题 实验题

木炭作为还原剂用于金属冶炼已有几千年历史。教材用如图甲实验介绍这一知识。  

(1)木炭与氧化铜反应的化学方程式是   ____________________________________;  

(2)木炭呈块状,实验时要先将木炭研细,再与CuO粉末混合均匀后使用。这样处理的目的是___________________________;  

(3)酒精灯火焰处加有铁丝网罩,其作用是_______________________________。

(4)为了提高成功率,某研究小组设计如图乙方案进行实验。

【装置改进】稳定的高温是本实验成功的关键因素之一,实验装置也会影响加热的效率。图乙将卧式装置改为直立式装置。实验时,将反应混合物夯实于试管底部,调节酒精灯时外焰完全包围试管的下部。你认为该设计是否更好?_________(填“是”或“否”);理由是__________________。

答案

(1) 2CuO+C2Cu+CO2

(2)使氧化铜和木炭粉末充分反应

(3)使火焰集中并提高温度

(4)是;反应物受热均匀,并可获得持续的高温

完形填空
完形填空。
    
     All the five 2008 Olympic mascots (吉祥物) have become top fashion. The more you know about them,
  1  you will understand the Olympics in China. Since China made its final decision at 8 p. m. November 11,
the five mascots have been seen everywhere. If you put their  2  together, they say "Beijing welcomes you!"
in Chinese. People rushed into many  3  to buy them. Some shelves were empty after only one day of
business.
     Do you know why the mascots  4  kids?" Children are the future of the world. So we have five childlike
mascots," said Wu Guanying, one of the designers. Wu  5  the idea of five dolls. When artists'finished the first
designs in April, they showed their work to some kids  6  if they liked them. They were quite happy at seeing
the lovely images (形象). They had many ideas about  7  they meant."There were all kinds of answers. Some
kids thought the mascots were a family of earth protectors (保护者). One even thought  8  was a daughter
of the sea." said Wu. An Olympic mascot is a symbol (标志) for the games. It's always an image with
something special for the people of  9 . Also, it carries people's  10  for the success of the games.
( )1. A. the earlier         
( )2. A. pictures            
( )3. A. big shopping centers
( )4. A. look at             
( )5. A. came on             
( )6. A. to see              
( )7. A. that                
( )8. A. the panda           
( )9. A. the host country    
( )10. A. congratulations    
B. better      
B. names       
B. museums     
B. look for    
B. came up with
B. seeing      
B. how         
B. the fire    
B. China       
B. best wishes 
C. the better     
C. colors         
C. libraries      
C. look like      
C. came from      
C. see            
C. what           
C. the fish                                 
C. the whole world
C. many thanks    
单项选择题