Wednesday, May 23, 2012

X CHEMICAL REACTION ASSIGNMENT


1.           Give an example of an exothermic reaction.                                                                          
2.           Write  electronic configuration of an element having atomic  number 13
3.           “Oxidation and  reduction processes occur simultaneously.”  Justify this statement with the help  of an example.
4.           “Barium chloride reacts  with  aluminium sulphate to give  aluminium chloride and  a precipitate of barium sulphate”
a.    Translate the  above  statement into  a chemical  equation.
b.    State two  types  in which  this  reaction can be classified.
5.           “A solution of potassium chloride when mixed  with silver  nitrate  solution, an insoluble white  substance is formed”.
a.       Translate the  above  statement into  a chemical  equation.
b.       State two types for this  reaction.
6.           Design an activity  to show a decomposition reaction in which light is used to decompose a reactant. Write  chemical  equation of the reaction and  state  its one use.
7.           State  the  reason why                                                                                                   
 (i)     an iron strip  dipped in a blue copper sulphate solution turns the blue solution pale  green.
(ii)     zinc is used  in the galvanisation of iron  and  not the copper.
8.           Why do we store silver chloride in dark coloured bottles?  Explain in brief.                           
9.           Draw a labelled schematic diagram to show the electrolysis of water.  Why is the amount of gas collected  in one of the test tubes  in this activity  double of the amount collected  in the other  ?
10.        What  happens when chlorine is passed over  dry  slaked time? Write  chemical  equation of the reaction involved.  Mention three  properties of the product.
11.       What  is meant by skeletal  equation ?                                                                                                
12.       What  is meant by thermal decomposition reaction ?  Explain  with  an example.                 
13.       An aluminium can is used  to store Ferrous sulphate solution. It is observed that in few days  holes  appeared in the can.   Explain  the observation and  write  chemical  equation to support your  answer.
14.       Give  three  differences between displacement and  double displacement reaction.               
15.       If copper  metal  is heated over  a flame,  it develops a coating.   What  is the  colour  and composition of this coating  ?
16.       What  change  will you observe if white  silver  chloride is placed  in sunlight ?  Write  an equation for the reaction and  the type  of the reaction.
17.       What  is Redox reaction ?  Identify the substance oxidised and  the substance reduced in the following reactions :
(i)      MnO2 + 4HCl  →   MnCl2  +2H2O + Cl2
(ii)     Cu0 +H2  →   Cu +H2O
18.       What  is the brown coloured gas evolved when lead nitrate crystals  are heated in  a dry test tube  ?
19.       Write  balanced equations for the reaction of :                                                                               
(a)     Iron  with  steam
(b)     Calcium with  water.
20.       On mixing  solutions of lead  nitrate and  potassium iodide in a test tube.                                   
(a)     Write  the chemical  equation involved in the balanced form.
(b)     What  is the colour  of the precipitate ?  Name  the precipitate.
21.       (a)     Write  one equation each  for decomposition reaction when energy is supplied in the form  of :      
 (i) heat                  (ii) light
(b)     Account for the  following.
(i)      Paint  is applied on iron  articles.
(ii)     Oil and  fat containing food  items  are flushed  with  nitrogen.
(iii)    When  an  iron  nail  kept  in  copper sulphate solution, blue  colour  of the solution fades  and  iron  nail becomes  brownish.
OR
(a)     What  do you  mean  by                                                                                                               
(i)      precipitation reaction (ii)     exothermic reaction (iii)    oxidation reaction
Write  balanced chemical  equation.
22.       A solution of potassium chloride when  mixed  with  silver  nitrate solution, an insoluble white  substance is formed.  Write  the chemical  reaction involved and  also mention the type  of the chemical  reaction ?
23.       Why do we store  silver  chloride in dark  coloured bottles  ?                                                     
24.       A magnesium ribbon  is burnt in oxygen  to give a white  compound X accompanied by  emission of light.
(a)     Write  the chemical  formulae of X
(b)     Write  a balanced chemical  equation, when X is dissolved in water.

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