试题与答案

不同季节的清晨，有时会看到卧室窗玻璃内侧表面有一层小水珠，有时是小冰花.请分别解释这

来源：www.tikuol.com
题型：问答题 简答题

题目：

不同季节的清晨，有时会看到卧室窗玻璃内侧表面有一层小水珠，有时是小冰花.请分别解释这两个现象，并说明发生这两种物态变化的条件有什么不同。

答案：

参考答案：

小水珠是室内空气中的水蒸气，遇到冷的玻璃，液化而成的：小冰花是室内空气中的水蒸气，遇到冷的玻璃，凝华而成的；两种物态变化中，水蒸气遇冷温度不同。凝华时遇冷温度低且低于零度。

考点：化学工程物理化学物理化学题库
试题推荐
题型：完形填空
完形填空。
     What must you do when you receive a present 1        your birthday? You have to sit down and write a thankyou note. The words "Thank you" are   2    important. We have to use them very often. We say them when someone gives us a drink,   3      us to pick up things, lends us a book or gives us a gift.
     Another important word is "please".   Many.people        4      to use it. It is rude to ask someone to do something without saying "please".We have to use it when we   5   something, too. It may be a book 6      a pencil, mor rice or help.  We have to use "please" to make the request pleasant.
     We have     7       "Sorry", too.  When we have   8  someone, we'll have to go up and say we're sorry.When we have forgotten something, we will also say "sorry".  We can make people     9 wrongs by saying it.
     These three words are  10      . Our children must learn to use them.  They are pleasing words to use in any languages.
( )1. A. in                    
( )2. A. so                    
( )3. A. helps                  
( )4. A. want                  
( )5. A. ask for                
( )6. A. but                    
( )7. A. learn to say          
( )8. A. fell                  
( )9. A. remember              
( )10.A. difficult but important		B. at                    
B. very                  
B. has                    
B. forget                
B. say                    
B. and                    
B.  to learn and say      
B. touched                
B. forget                
B.  simple but important  		C. for                    
C. rather                
C. lets                  
C. like                  
C. need                  
C. or                    
C.  learn and say        
C. felt                  
C. need                  
C.  useful but difficult  		D. to                     
D. such                      
D. makes                      
D. remember                  
D. want                      
D. as                        
D.  to learn to say       
D. hurt                      
D. think                      
D.  helpful but difficult    
查看答案
微信公众账号搜索答案