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CBSE Notes 2011-2012

science ..guess paper..! think dis may help u..!

Guess Paper – 2012
Class – X
Subject –
SCIENCE                    

                   
Q-1  why does the sun appear reddish at sunrise?
Q-2  From amongst the metals Na, Mg, Ca, Al, Cu, Name the metal
        (i) which reacts with water only on boiling
        (ii) which do not react even on steam.
 
Q-3  (a) Show the formation of Na2O by transfer of electrons between the           
              combining  atoms.
         (b) why the ionic compounds usually hard?
         (c)  How is that ionic compounds do not conduct electricity in solid state but  
               they do so in molten state?
 
Q-4  Draw a diagram to show the formation of image of a distinct object by a   
        myopic eye. How such an eye can be remedied? State two reason due to  
         which this defect may be caused?
 
Q-5  Why does  carbon form compounds mainly by covalent bonding? List any  
         reason for carbon forming a large number of compounds?
 
Q-6  What is a homologous series of a compounds. List any two characteristics of  
         a homologous series.
                                                                          
Q-7  How would you distinguish experimentally between an alcohol and a   
         carboxylic acid on the basis of a chemical property.
 
Q-8  Why red colour is used to show the sign of danger?
 
Q-9  State reason:
              (i) Why ionic compounds have high melting and boiling points.
              (ii) Metals are good conductor of electricity but Non-metals are not.